Prophylactic anticoagulants for non-hospitalised people with COVID-19.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic has impacted healthcare systems worldwide. Multiple reports on thromboembolic complications related to COVID-19 have been published, and researchers have described that people with COVID-19 are at high risk for developing venous thromboembolism (VTE). Anticoagulants have been used as pharmacological interventions to prevent arterial and venous thrombosis, and their use in the outpatient setting could potentially reduce the prevalence of vascular thrombosis and associated mortality in people with COVID-19. However, even lower doses used for a prophylactic purpose may result in adverse events such as bleeding. It is important to consider the evidence for anticoagulant use in non-hospitalised people with COVID-19. OBJECTIVES: To evaluate the benefits and harms of prophylactic anticoagulants versus active comparators, placebo or no intervention, or non-pharmacological interventions in non-hospitalised people with COVID-19. SEARCH METHODS: We used standard, extensive Cochrane search methods. The latest search date was 18 April 2022. SELECTION CRITERIA: We included randomised controlled trials (RCTs) comparing prophylactic anticoagulants with placebo or no treatment, another active comparator, or non-pharmacological interventions in non-hospitalised people with COVID-19. We included studies that compared anticoagulants with a different dose of the same anticoagulant. We excluded studies with a duration of under two weeks. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methodological procedures. Our primary outcomes were all-cause mortality, VTE (deep vein thrombosis (DVT) or pulmonary embolism (PE)), and major bleeding. Our secondary outcomes were DVT, PE, need for hospitalisation, minor bleeding, adverse events, and quality of life. We used GRADE to assess the certainty of the evidence. MAIN RESULTS: We included five RCTs with up to 90 days of follow-up (short term). Data were available for meta-analysis from 1777 participants. Anticoagulant compared to placebo or no treatment Five studies compared anticoagulants with placebo or no treatment and provided data for three of our outcomes of interest (all-cause mortality, major bleeding, and adverse events). The evidence suggests that prophylactic anticoagulants may lead to little or no difference in all-cause mortality (risk ratio (RR) 0.36, 95% confidence interval (CI) 0.04 to 3.61; 5 studies; 1777 participants; low-certainty evidence) and probably reduce VTE from 3% in the placebo group to 1% in the anticoagulant group (RR 0.36, 95% CI 0.16 to 0.85; 4 studies; 1259 participants; number needed to treat for an additional beneficial outcome (NNTB) = 50; moderate-certainty evidence). There may be little to no difference in major bleeding (RR 0.36, 95% CI 0.01 to 8.78; 5 studies; 1777 participants; low-certainty evidence). Anticoagulants probably result in little or no difference in DVT (RR 1.02, 95% CI 0.30 to 3.46; 3 studies; 1009 participants; moderate-certainty evidence), but probably reduce the risk of PE from 2.7% in the placebo group to 0.7% in the anticoagulant group (RR 0.25, 95% CI 0.08 to 0.79; 3 studies; 1009 participants; NNTB 50; moderate-certainty evidence). Anticoagulants probably lead to little or no difference in reducing hospitalisation (RR 1.01, 95% CI 0.59 to 1.75; 4 studies; 1459 participants; moderate-certainty evidence) and may lead to little or no difference in adverse events (minor bleeding, RR 2.46, 95% CI 0.90 to 6.72; 5 studies, 1777 participants; low-certainty evidence). Anticoagulant compared to a different dose of the same anticoagulant One study compared anticoagulant (higher-dose apixaban) with a different (standard) dose of the same anticoagulant and reported five relevant outcomes. No cases of all-cause mortality, VTE, or major bleeding occurred in either group during the 45-day follow-up (moderate-certainty evidence). Higher-dose apixaban compared to standard-dose apixaban may lead to little or no difference in reducing the need for hospitalisation (RR 1.89, 95% CI 0.17 to 20.58; 1 study; 278 participants; low-certainty evidence) or in the number of adverse events (minor bleeding, RR 0.47, 95% CI 0.09 to 2.54; 1 study; 278 participants; low-certainty evidence). Anticoagulant compared to antiplatelet agent One study compared anticoagulant (apixaban) with antiplatelet agent (aspirin) and reported five relevant outcomes. No cases of all-cause mortality or major bleeding occurred during the 45-day follow-up (moderate-certainty evidence). Apixaban may lead to little or no difference in VTE (RR 0.36, 95% CI 0.01 to 8.65; 1 study; 279 participants; low-certainty evidence), need for hospitalisation (RR 3.20, 95% CI 0.13 to 77.85; 1 study; 279 participants; low-certainty evidence), or adverse events (minor bleeding, RR 2.13, 95% CI 0.40 to 11.46; 1 study; 279 participants; low-certainty evidence). No included studies reported on quality of life or investigated anticoagulants compared to a different anticoagulant, or anticoagulants compared to non-pharmacological interventions. AUTHORS' CONCLUSIONS: We found low- to moderate-certainty evidence from five RCTs that prophylactic anticoagulants result in little or no difference in major bleeding, DVT, need for hospitalisation, or adverse events when compared with placebo or no treatment in non-hospitalised people with COVID-19. Low-certainty evidence indicates that prophylactic anticoagulants may result in little or no difference in all-cause mortality when compared with placebo or no treatment, but moderate-certainty evidence indicates that prophylactic anticoagulants probably reduce the incidence of VTE and PE. Low-certainty evidence suggests that comparing different doses of the same prophylactic anticoagulant may result in little or no difference in need for hospitalisation or adverse events. Prophylactic anticoagulants may result in little or no difference in risk of VTE, hospitalisation, or adverse events when compared with antiplatelet agents (low-certainty evidence). Given that there were only short-term data from one study, these results should be interpreted with caution. Additional trials of sufficient duration are needed to clearly determine any effect on clinical outcomes.

Pharmacological interventions for asymptomatic carotid stenosis.

BACKGROUND: Carotid artery stenosis is narrowing of the carotid arteries. Asymptomatic carotid stenosis is when this narrowing occurs in people without a history or symptoms of this disease. It is caused by atherosclerosis; that is, the build-up of fats, cholesterol, and other substances in and on the artery walls. Atherosclerosis is more likely to occur in people with several risk factors, such as diabetes, hypertension, hyperlipidaemia, and smoking. As this damage can develop without symptoms, the first symptom can be a fatal or disabling stroke, known as ischaemic stroke. Carotid stenosis leading to ischaemic stroke is most common in men older than 70 years. Ischaemic stroke is a worldwide public health problem. OBJECTIVES: To assess the effects of pharmacological interventions for the treatment of asymptomatic carotid stenosis in preventing neurological impairment, ipsilateral major or disabling stroke, death, major bleeding, and other outcomes. SEARCH METHODS: We searched the Cochrane Stroke Group trials register, CENTRAL, MEDLINE, Embase, two other databases, and three trials registers from their inception to 9 August 2022. We also checked the reference lists of any relevant systematic reviews identified and contacted specialists in the field for additional references to trials. SELECTION CRITERIA: We included all randomised controlled trials (RCTs), irrespective of publication status and language, comparing a pharmacological intervention to placebo, no treatment, or another pharmacological intervention for asymptomatic carotid stenosis. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methodological procedures. Two review authors independently extracted the data and assessed the risk of bias of the trials. A third author resolved disagreements when necessary. We assessed the evidence certainty for key outcomes using GRADE. MAIN RESULTS: We included 34 RCTs with 11,571 participants. Data for meta-analysis were available from only 22 studies with 6887 participants. The mean follow-up period was 2.5 years. None of the 34 included studies assessed neurological impairment and quality of life. Antiplatelet agent (acetylsalicylic acid) versus placebo Acetylsalicylic acid (1 study, 372 participants) may result in little to no difference in ipsilateral major or disabling stroke (risk ratio (RR) 1.08, 95% confidence interval (CI) 0.47 to 2.47), stroke-related mortality (RR 1.40, 95% CI 0.54 to 3.59), progression of carotid stenosis (RR 1.16, 95% CI 0.79 to 1.71), and adverse events (RR 0.81, 95% CI 0.41 to 1.59), compared to placebo (all low-certainty evidence). The effect of acetylsalicylic acid on major bleeding is very uncertain (RR 0.98, 95% CI 0.06 to 15.53; very low-certainty evidence). The study did not measure neurological impairment or quality of life. Antihypertensive agents (metoprolol and chlorthalidone) versus placebo The antihypertensive agent, metoprolol, may result in no difference in ipsilateral major or disabling stroke (RR 0.14, 95% CI 0.02 to1.16; 1 study, 793 participants) and stroke-related mortality (RR 0.57, 95% CI 0.17 to 1.94; 1 study, 793 participants) compared to placebo (both low-certainty evidence). However, chlorthalidone may slow the progression of carotid stenosis (RR 0.45, 95% CI 0.23 to 0.91; 1 study, 129 participants; low-certainty evidence) compared to placebo. Neither study measured neurological impairment, major bleeding, adverse events, or quality of life. Anticoagulant agent (warfarin) versus placebo The evidence is very uncertain about the effects of warfarin (1 study, 919 participants) on major bleeding (RR 1.19, 95% CI 0.97 to 1.46; very low-certainty evidence), but it may reduce adverse events (RR 0.89, 95% CI 0.81 to 0.99; low-certainty evidence) compared to placebo. The study did not measure neurological impairment, ipsilateral major or disabling stroke, stroke-related mortality, progression of carotid stenosis, or quality of life. Lipid-lowering agents (atorvastatin, fluvastatin, lovastatin, pravastatin, probucol, and rosuvastatin) versus placebo or no treatment Lipid-lowering agents may result in little to no difference in ipsilateral major or disabling stroke (atorvastatin, lovastatin, pravastatin, and rosuvastatin; RR 0.36, 95% CI 0.09 to 1.53; 5 studies, 2235 participants) stroke-related mortality (lovastatin and pravastatin; RR 0.25, 95% CI 0.03 to 2.29; 2 studies, 1366 participants), and adverse events (fluvastatin, lovastatin, pravastatin, probucol, and rosuvastatin; RR 0.76, 95% CI 0.53 to1.10; 7 studies, 3726 participants) compared to placebo or no treatment (all low-certainty evidence). The studies did not measure neurological impairment, major bleeding, progression of carotid stenosis, or quality of life. AUTHORS' CONCLUSIONS: Although there is no high-certainty evidence to support pharmacological intervention, this does not mean that pharmacological treatments are ineffective in preventing ischaemic cerebral events, morbidity, and mortality. High-quality RCTs are needed to better inform the best medical treatment that may reduce the burden of carotid stenosis. In the interim, clinicians will have to use other sources of information.

Duplex ultrasound for surveillance of lower limb revascularisation.

BACKGROUND: Lower extremity atherosclerotic disease (LEAD) - also known as peripheral arterial disease - refers to the obstruction or narrowing of the large arteries of the lower limbs, most commonly caused by atheromatous plaque. Although in many cases of less severe disease patients can be asymptomatic, the major clinical manifestations of LEAD are intermittent claudication (IC) and critical limb ischaemia, also known as chronic limb-threatening ischaemia (CLTI). Revascularisation procedures including angioplasty, stenting, and bypass grafting may be required for those in whom the disease is severe or does not improve with non-surgical interventions. Maintaining vessel patency after revascularisation remains a challenge for vascular surgeons, since approximately 30% of vein grafts may present with restenosis in the first year due to myointimal hyperplasia. Restenosis can also occur after angioplasty and stenting. Restenosis and occlusions that occur more than two years after the procedure are generally related to progression of the atherosclerosis. Surveillance programmes with duplex ultrasound (DUS) scanning as part of postoperative care may facilitate early diagnosis of restenosis and help avoid amputation in people who have undergone revascularisation. OBJECTIVES: To assess the effects of DUS versus pulse palpation, arterial pressure index, angiography, or any combination of these, for surveillance of lower limb revascularisation in people with LEAD. SEARCH METHODS: The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL, and LILACS databases and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 1 February 2022. SELECTION CRITERIA: We included randomised controlled trials (RCTs) and quasi-RCTs that compared DUS surveillance after lower limb revascularisation versus clinical surveillance characterised by medical examination with pulse palpation, with or without any other objective test, such as arterial pressure index measures (e.g. ankle-brachial index (ABI) or toe brachial index (TBI)). Our primary outcomes were limb salvage rate, vessel or graft secondary patency, and adverse events resulting from DUS surveillance. Secondary outcomes were all-cause mortality, functional walking ability assessed by walking distance, clinical severity scales, quality of life (QoL), re-intervention rates, and functional walking ability assessed by any validated walking impairment questionnaire. We presented the outcomes at two time points: two years or less after the original revascularisation (short term) and more than two years after the original revascularisation (long term). DATA COLLECTION AND ANALYSIS: We used standard Cochrane methodological procedures. We used the Cochrane RoB 1 tool to assess the risk of bias for RCTs and GRADE to assess the certainty of evidence. We performed meta-analysis when appropriate. MAIN RESULTS: We included three studies (1092 participants) that compared DUS plus pulse palpation and arterial pressure index (ABI or TBI) versus pulse palpation and arterial pressure index (ABI or TBI) for surveillance of lower limb revascularisation with bypass. One study each was conducted in Sweden and Finland, and the third study was conducted in the UK and Europe. The studies did not report adverse events resulting from DUS surveillance, functional walking ability, or clinical severity scales. No study assessed surveillance with DUS scanning after angioplasty or stenting, or both. We downgraded the certainty of evidence for risk of bias and imprecision. Duplex ultrasound plus pulse palpation and arterial pressure index (ABI or TBI) versus pulse palpation plus arterial pressure index (ABI or TBI) (short-term time point) In the short term, DUS surveillance may lead to little or no difference in limb salvage rate (risk ratio (RR) 0.84, 95% confidence interval (CI) 0.49 to 1.45; I² = 93%; 2 studies, 936 participants; low-certainty evidence) and vein graft secondary patency (RR 0.92, 95% CI 0.67 to 1.26; I² = 57%; 3 studies, 1092 participants; low-certainty evidence). DUS may lead to little or no difference in all-cause mortality (RR 1.11, 95% CI 0.70 to 1.74; 1 study, 594 participants; low-certainty evidence). There was no clear difference in QoL as assessed by the 36-item Short Form Health Survey (SF-36) physical score (mean difference (MD) 2 higher, 95% CI 2.59 lower to 6.59 higher; 1 study, 594 participants; low-certainty evidence); the SF-36 mental score (MD 3 higher, 95% CI 0.38 lower to 6.38 higher; 1 study, 594 participants; low-certainty evidence); or the EQ-5D utility score (MD 0.02 higher, 95% CI 0.03 lower to 0.07 higher; 1 study, 594 participants; low-certainty evidence). DUS may increase re-intervention rates when considered any therapeutic intervention (RR 1.38, 95% CI 1.05 to 1.81; 3 studies, 1092 participants; low-certainty evidence) or angiogram procedures (RR 1.53, 95% CI 1.12 to 2.08; 3 studies, 1092 participants; low-certainty evidence). Duplex ultrasound plus pulse palpation and arterial pressure index (ABI or TBI) versus pulse palpation plus arterial pressure index (ABI or TBI) (long-term time point) One study reported data after two years, but provided only vessel or graft secondary patency data. DUS may lead to little or no difference in vessel or graft secondary patency (RR 0.83, 95% CI 0.19 to 3.51; 1 study, 156 participants; low-certainty evidence). Other outcomes of interest were not reported at the long-term time point. AUTHORS' CONCLUSIONS: Based on low certainty evidence, we found no clear difference between DUS and standard surveillance in preventing limb amputation, morbidity, and mortality after lower limb revascularisation. We found no studies on DUS surveillance after angioplasty or stenting (or both), only studies on bypass grafting. High-quality RCTs should be performed to better inform the best medical surveillance of lower limb revascularisation that may reduce the burden of peripheral arterial disease.

Pharmacological interventions for preventing venous thromboembolism in people undergoing bariatric surgery.

BACKGROUND: Venous thromboembolism (VTE), which comprises deep vein thrombosis (DVT) and pulmonary embolism (PE), is the leading cause of preventable death in hospitalised people and the third most common cause of mortality in surgical patients. People undergoing bariatric surgery have the additional risk factor of being overweight. Although VTE prophylaxis in surgical patients is well established, the best way to prevent VTE in those undergoing bariatric surgery is less clear. OBJECTIVES: To evaluate the benefits and harms of pharmacological interventions (alone or in combination) on venous thromboembolism and other health outcomes in people undergoing bariatric surgery compared to the same pharmacological intervention administered at a different dose or frequency, the same pharmacological intervention or started at a different time point, another pharmacological intervention, no intervention or placebo. SEARCH METHODS: We used standard, extensive Cochrane search methods. The latest search date was 1 November 2021. SELECTION CRITERIA: We included randomised controlled trials (RCTs) and quasi-RCTs in males and females of any age undergoing bariatric surgery comparing pharmacological interventions for VTE (alone or in combination) with the same pharmacological intervention administered at a different dose or frequency, the same pharmacological intervention started at a different time point, a different pharmacological intervention, no treatment or placebo. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methods. Our primary outcomes were 1. VTE and 2. major bleeding. Our secondary outcomes were 1. all-cause mortality, 2. VTE-related mortality, 3. PE, 4. DVT, 5. adverse effects and 6. quality of life. We used GRADE to assess certainty of evidence for each outcome. MAIN RESULTS: We included seven RCTs with 1045 participants. Data for meta-analysis were available from all participants. Four RCTs (597 participants) compared higher-dose heparin to standard-dose heparin: one of these studies (139 participants) used unfractionated heparin (UFH) and the other three (458 participants) used low-molecular-weight heparin (LMWH). One study compared heparin versus pentasaccharide (198 participants), and one study compared starting heparin before versus after bariatric surgery (100 participants). One study (150 participants) compared combined mechanical and pharmacological (enoxaparin) prophylaxis versus mechanical prophylaxis alone. The duration of the interventions ranged from seven to 15 days, and follow-up ranged from 10 to 180 days. Higher-dose heparin versus standard-dose heparin Compared to standard-dose heparin, higher-dose heparin may result in little or no difference in the risk of VTE (RR 0.55, 95% CI 0.05 to 5.99; 4 studies, 597 participants) or major bleeding (RR 1.19, 95% CI 0.48 to 2.96; I2 = 8%; 4 studies, 597 participants; low-certainty) in people undergoing bariatric surgery. The evidence on all-cause mortality, VTE-related mortality, PE, DVT and adverse events (thrombocytopenia) is uncertain (effect not estimable or very low-certainty evidence). Heparin versus pentasaccharide Heparin compared to a pentasaccharide after bariatric surgery may result in little or no difference in the risk of VTE (RR 0.83, 95% CI 0.19 to 3.61; 1 study, 175 participants) or DVT (RR 0.83, 95% CI 0.19 to 3.61; 1 study, 175 participants). The evidence on major bleeding, PE and mortality is uncertain (effect not estimable or very low-certainty evidence). Heparin started before versus after the surgical procedure Starting prophylaxis with heparin 12 hours before surgery versus after surgery may result in little or no difference in the risk of VTE (RR 0.11, 95% CI 0.01 to 2.01; 1 study, 100 participants) or DVT (RR 0.11, 95% CI 0.01 to 2.01; 1 study, 100 participants). The evidence on major bleeding, all-cause mortality and VTE-related mortality is uncertain (effect not estimable or very low-certainty evidence). We were unable to assess the effect of this intervention on PE or adverse effects, as the study did not measure these outcomes. Combined mechanical and pharmacological prophylaxis versus mechanical prophylaxis alone Combining mechanical and pharmacological prophylaxis (started 12 hours before surgery) may reduce VTE events in people undergoing bariatric surgery compared to mechanical prophylaxis alone (RR 0.05, 95% CI 0.00 to 0.89; number needed to treat for an additional beneficial outcome (NNTB) = 9; 1 study, 150 participants; low-certainty). We were unable to assess the effect of this intervention on major bleeding or morality (effect not estimable), or on PE or adverse events (not measured). No studies measured quality of life. AUTHORS' CONCLUSIONS: Higher-dose heparin may make little or no difference to venous thromboembolism or major bleeding in people undergoing bariatric surgery when compared to standard-dose heparin. Heparin may make little or no difference to venous thromboembolism in people undergoing bariatric surgery when compared to pentasaccharide. There are inadequate data to draw conclusions about the effects of heparin compared to pentasaccharide on major bleeding. Starting prophylaxis with heparin 12 hours before bariatric surgery may make little or no difference to venous thromboembolism in people undergoing bariatric surgery when compared to starting heparin after bariatric surgery. There are inadequate data to draw conclusions about the effects of heparin started before versus after surgery on major bleeding. Combining mechanical and pharmacological prophylaxis (started 12 hours before surgery) may reduce VTE events in people undergoing bariatric surgery when compared to mechanical prophylaxis alone. No data are available relating to major bleeding. The certainty of the evidence is limited by small sample sizes, few or no events, and risk of bias concerns. Future trials must be sufficiently large to enable analysis of relevant clinical outcomes, and should standardise the time of treatment and follow-up. They should also address the effect of direct oral anticoagulants and antiplatelets, preferably grouping them according to the type of intervention.

Antiplatelet agents for the treatment of deep venous thrombosis.

BACKGROUND: Antiplatelet agents may be useful for the treatment of deep venous thrombosis (DVT) when used in addition to best medical practice (BMP), which includes anticoagulation, compression stockings, and clinical care such as physical exercise, skin hydration, etc. Antiplatelet agents could minimise complications such as post-thrombotic syndrome (PTS) and pulmonary embolism (PE). They may also reduce the recurrence of the disease (recurrent venous thromboembolism (recurrent VTE)). However, antiplatelet agents may increase the likelihood of bleeding events. OBJECTIVES: To assess the effects of antiplatelet agents in addition to current BMP compared to current BMP (with or without placebo) for the treatment of DVT. SEARCH METHODS: The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase and CINAHL databases and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 7 December 2021. The review authors searched LILACS and IBECS databases (15 December 2021) and also checked the bibliographies of included trials for further references to relevant trials, and contacted specialists in the field, manufacturers and authors of the included trials. SELECTION CRITERIA: We considered randomised controlled trials (RCTs) examining antiplatelet agents compared to BMP following initial standard anticoagulation treatment for DVT. We included studies where antiplatelet agents were given in addition to current BMP compared to current BMP (with or without placebo) for the treatment of DVT (acute: treatment started within 21 days of symptom onset; chronic: treatment started after 21 days of symptom onset). We evaluated only RCTs where the antiplatelet agents were the unique difference between the groups (intervention and control). DATA COLLECTION AND ANALYSIS: We used standard Cochrane methodological procedures. Two review authors independently extracted data and assessed risk of bias of the trials. Any disagreements were resolved by discussion with a third review author. We calculated outcome effects using risk ratio (RR) or mean difference (MD) with a 95% confidence interval (CI) and the number needed to treat to benefit (NNTB). MAIN RESULTS: We included six studies with 1625 eligible participants, with data up to 37.2 months of follow-up. For one preplanned comparison (i.e. antiplatelet agents plus BMP versus BMP plus placebo) for acute DVT we identified no eligible studies for inclusion. In acute DVT, antiplatelet agents plus BMP versus BMP alone was assessed by one study (500 participants), which reported on four outcomes until 6 months of follow-up. There were no deaths and no cases of major bleeding reported. The participants who received antiplatelet agents showed a lower risk of PTS (RR 0.74, 95% CI 0.61 to 0.91; 1 study, 500 participants; very low-certainty evidence). The control group presented a lower risk of adverse events compared to the intervention group (RR 2.88, 95% CI 1.06 to 7.80; 1 study, 500 participants; very low-certainty evidence). This study did not provide information for recurrent VTE or PE. In chronic DVT, antiplatelet agents plus BMP versus BMP alone was assessed by one study (224 participants). The study authors reported four relevant outcomes, three of which (major bleeding, mortality and adverse events) showed no events during the 3 years of follow-up. Therefore, an effect estimate could only be reported for recurrent VTE, favouring antiplatelet agents plus BMP versus BMP alone (RR 0.12, 95% CI 0.05 to 0.34; 1 study, 224 participants; very low-certainty evidence). For the outcomes PE and PTS, this study did not present information which could be used for analysis. In chronic DVT, antiplatelet agents plus BMP versus BMP plus placebo was assessed by four studies (901 participants). The meta-analysis of this pooled data showed a lower risk of recurrent VTE for the antiplatelet agents group (RR 0.65, 95%, CI 0.43 to 0.96; NNTB = 14; low-certainty evidence). For major bleeding, we found no clear difference between placebo and intervention groups until 37.2 months of follow-up (RR 0.98, 95% CI 0.29 to 3.34; 1 study, 583 participants; moderate-certainty evidence). In PE fatal/non-fatal outcome, we found no clear difference with the use of antiplatelet agents (RR 0.52, 95% CI 0.23 to 1.14; 1 study, 583 participants; moderate-certainty evidence). For all-cause mortality, the overall effect of antiplatelet agents did not differ from the placebo group (RR 0.48, 95% CI 0.21 to 1.06; 3 studies, 649 participants; moderate-certainty evidence). The adverse events outcome did not show a clear difference (RR 1.57, 95% CI 0.34 to 7.19; 2 studies, 621 participants; moderate-certainty evidence). There is no assessment of PTS in these studies. We downgraded the certainty of evidence for risk of bias, indirectness, imprecision and publication bias. AUTHORS' CONCLUSIONS: In chronic DVT settings, following the initial standard treatment with anticoagulants, there is low-certainty evidence that antiplatelet agents in addition to BMP may reduce recurrent VTE, (NNTB = 14) when compared to BMP plus placebo. Moderate-certainty evidence shows no clear difference in adverse events, major bleeding and PE when antiplatelet agents are used in addition to BMP compared to BMP plus placebo. In acute and chronic DVT settings, following the initial standard treatment with anticoagulants, we can draw no conclusions for antiplatelet agents in addition to BMP compared to BMP alone due to very low-certainty evidence.  Trials of high methodological quality, that are large and of sufficient duration to detect significant clinical outcomes are needed. Trials should ideally last more than 4 years in order to estimate the long-term effect of antiplatelet agents. Trials should include people with acute and chronic DVT and provide relevant individual data, such as the outcome for each index event (DVT or PE), the use of an inferior vena cava (IVC) filter, whether the DVT is provoked or unprovoked, and the age of participants.

Type of anaesthesia for acute ischaemic stroke endovascular treatment.

BACKGROUND: The use of mechanical thrombectomy to restore intracranial blood flow after proximal large artery occlusion by a thrombus has increased over time and led to better outcomes than intravenous thrombolytic therapy alone. Currently, the type of anaesthetic technique during mechanical thrombectomy is under debate as having a relevant impact on neurological outcomes. OBJECTIVES: To assess the effects of different types of anaesthesia for endovascular interventions in people with acute ischaemic stroke. SEARCH METHODS: We searched the Cochrane Stroke Group Specialised Register of Trials on 5 July 2022, and CENTRAL, MEDLINE, and seven other databases on 21 March 2022. We performed searches of reference lists of included trials, grey literature sources, and other systematic reviews.  SELECTION CRITERIA: We included all randomised controlled trials with a parallel design that compared general anaesthesia versus local anaesthesia, conscious sedation anaesthesia, or monitored care anaesthesia for mechanical thrombectomy in acute ischaemic stroke. We also included studies reported as full-text, those published as abstract only, and unpublished data. We excluded quasi-randomised trials, studies without a comparator group, and studies with a retrospective design. DATA COLLECTION AND ANALYSIS: Two review authors independently applied the inclusion criteria, extracted data, and assessed the risk of bias and the certainty of the evidence using the GRADE approach. The outcomes were assessed at different time periods, ranging from the onset of the stroke symptoms to 90 days after the start of the intervention. The main outcomes were functional outcome, neurological impairment, stroke-related mortality, all intracranial haemorrhage, target artery revascularisation status, time to revascularisation, adverse events, and quality of life. All included studies reported data for early (up to 30 days) and long-term (above 30 days) time points. MAIN RESULTS: We included seven trials with 982 participants, which investigated the type of anaesthesia for endovascular treatment in large vessel occlusion in the intracranial circulation. The outcomes were assessed at different time periods, ranging from the onset of stroke symptoms to 90 days after the procedure. Therefore, all included studies reported data for early (up to 30 days) and long-term (above 30 up to 90 days) time points. General anaesthesia versus non-general anaesthesia(early) We are uncertain about the effect of general anaesthesia on functional outcomes compared to non-general anaesthesia (mean difference (MD) 0, 95% confidence interval (CI) -0.31 to 0.31; P = 1.0; 1 study, 90 participants; very low-certainty evidence) and in time to revascularisation from groin puncture until the arterial reperfusion (MD 2.91 minutes, 95% CI -5.11 to 10.92; P = 0.48; I² = 48%; 5 studies, 498 participants; very low-certainty evidence). General anaesthesia may lead to no difference in neurological impairment up to 48 hours after the procedure (MD -0.29, 95% CI -1.18 to 0.59; P = 0.52; I² = 0%; 7 studies, 982 participants; low-certainty evidence), and in stroke-related mortality (risk ratio (RR) 0.98, 95% CI 0.52 to 1.84; P = 0.94; I² = 0%; 3 studies, 330 participants; low-certainty evidence), all intracranial haemorrhages (RR 0.92, 95% CI 0.65 to 1.29; P = 0.63; I² = 0%; 5 studies, 693 participants; low-certainty evidence) compared to non-general anaesthesia. General anaesthesia may improve adverse events (haemodynamic instability) compared to non-general anaesthesia (RR 0.21, 95% CI 0.05 to 0.79; P = 0.02; I² = 71%; 2 studies, 229 participants; low-certainty evidence). General anaesthesia improves target artery revascularisation compared to non-general anaesthesia (RR 1.10, 95% CI 1.02 to 1.18; P = 0.02; I² = 29%; 7 studies, 982 participants; moderate-certainty evidence). There were no available data for quality of life. General anaesthesia versus non-general anaesthesia (long-term) There is no difference in general anaesthesia compared to non-general anaesthesia for dichotomous and continuous functional outcomes (dichotomous: RR 1.21, 95% CI 0.93 to 1.58; P = 0.16; I² = 29%; 4 studies, 625 participants; low-certainty evidence; continuous: MD -0.14, 95% CI -0.34 to 0.06; P = 0.17; I² = 0%; 7 studies, 978 participants; low-certainty evidence). General anaesthesia showed no changes in stroke-related mortality compared to non-general anaesthesia (RR 0.88, 95% CI 0.64 to 1.22; P = 0.44; I² = 12%; 6 studies, 843 participants; low-certainty evidence). There were no available data for neurological impairment, all intracranial haemorrhages, target artery revascularisation status, time to revascularisation from groin puncture until the arterial reperfusion, adverse events (haemodynamic instability), or quality of life. Ongoing studies We identified eight ongoing studies. Five studies compared general anaesthesia versus conscious sedation anaesthesia, one study compared general anaesthesia versus conscious sedation anaesthesia plus local anaesthesia, and two studies compared general anaesthesia versus local anaesthesia. Of these studies, seven plan to report data on functional outcomes using the modified Rankin Scale, five studies on neurological impairment, six studies on stroke-related mortality, two studies on all intracranial haemorrhage, five studies on target artery revascularisation status, four studies on time to revascularisation, and four studies on adverse events. One ongoing study plans to report data on quality of life. One study did not plan to report any outcome of interest for this review. AUTHORS' CONCLUSIONS: In early outcomes, general anaesthesia improves target artery revascularisation compared to non-general anaesthesia with moderate-certainty evidence. General anaesthesia may improve adverse events (haemodynamic instability) compared to non-general anaesthesia with low-certainty evidence. We found no evidence of a difference in neurological impairment, stroke-related mortality, all intracranial haemorrhage and haemodynamic instability adverse events between groups with low-certainty evidence. We are uncertain whether general anaesthesia improves functional outcomes and time to revascularisation because the certainty of the evidence is very low. However, regarding long-term outcomes, general anaesthesia makes no difference to functional outcomes compared to non-general anaesthesia with low-certainty evidence. General anaesthesia did not change stroke-related mortality when compared to non-general anaesthesia with low-certainty evidence. There were no reported data for other outcomes. In view of the limited evidence of effect, more randomised controlled trials with a large number of participants and good protocol design with a low risk of bias should be performed to reduce our uncertainty and to aid decision-making in the choice of anaesthesia.

Duplex ultrasound for diagnosing symptomatic carotid stenosis in the extracranial segments.

BACKGROUND: Carotid artery stenosis is an important cause of stroke and transient ischemic attack. Correctly and rapidly identifying patients with symptomatic carotid artery stenosis is essential for adequate treatment with early cerebral revascularization. Doubts about the diagnostic value regarding the accuracy of duplex ultrasound (DUS) and the possibility of using DUS as the single diagnostic test before carotid revascularization are still debated. OBJECTIVES: To estimate the accuracy of DUS in individuals with symptomatic carotid stenosis verified by either digital subtraction angiography (DSA), computed tomography angiography (CTA), or magnetic resonance angiography (MRA). SEARCH METHODS: We searched CRDTAS, CENTRAL, MEDLINE (Ovid), Embase (Ovid), ISI Web of Science, HTA, DARE, and LILACS up to 15 February 2021. We handsearched the reference lists of all included studies and other relevant publications and contacted experts in the field to identify additional studies or unpublished data. SELECTION CRITERIA: We included studies assessing DUS accuracy against an acceptable reference standard (DSA, MRA, or CTA) in symptomatic patients. We considered the classification of carotid stenosis with DUS defined with validated duplex velocity criteria, and the NASCET criteria for carotid stenosis measures on DSA, MRA, and CTA. We excluded studies that included < 70% of symptomatic patients; the time between the index test and the reference standard was longer than four weeks or not described, or that presented no objective criteria to estimate carotid stenosis. DATA COLLECTION AND ANALYSIS: The review authors independently screened articles, extracted data, and assessed the risk of bias and applicability concerns using the QUADAS-2 domain list. We extracted data with an effort to complete a 2 × 2 table (true positives, true negatives, false positives, and false negatives) for each of the different categories of carotid stenosis and reference standards. We produced forest plots and summary receiver operating characteristic (ROC) plots to summarize the data. Where meta-analysis was possible, we used a bivariate meta-analysis model. MAIN RESULTS: We identified 25,087 unique studies, of which 22 were deemed eligible for inclusion (4957 carotid arteries). The risk of bias varied considerably across the studies, and studies were generally of moderate to low quality. We narratively described the results without meta-analysis in seven studies in which the criteria used to determine stenosis were too different from the duplex velocity criteria proposed in our protocol or studies that provided insufficient data to complete a 2 × 2 table for at least in one category of stenosis. Nine studies (2770 carotid arteries) presented DUS versus DSA results for 70% to 99% carotid artery stenosis, and two (685 carotid arteries) presented results from DUS versus CTA in this category. Seven studies presented results for occlusion with DSA as the reference standard and three with CTA as the reference standard. Five studies compared DUS versus DSA for 50% to 99% carotid artery stenosis. Only one study presented results from 50% to 69% carotid artery stenosis. For DUS versus DSA, for < 50% carotid artery stenosis, the summary sensitivity was 0.63 (95% confidence interval [CI] 0.48 to 0.76) and the summary specificity was 0.99 (95% CI 0.96 to 0.99); for the 50% to 69% range, only one study was included and meta-analysis not performed; for the 50% to 99% range, the summary sensitivity was 0.97 (95% CI 0.95 to 0.98) and the summary specificity was 0.70 (95% CI 0.67 to 0.73); for the 70% to 99% range, the summary sensitivity was 0.85 (95% CI 0.77 to 0.91) and the summary specificity was 0.98 (95% CI 0.74 to 0.90); for occlusion, the summary sensitivity was 0.91 (95% CI 0.81 to 0.97) and the summary specificity was 0.95 (95% CI 0.76 to 0.99). For sensitivity analyses, excluding studies in which participants were selected based on the presence of occlusion on DUS had an impact on specificity: 0.98 (95% CI 0.97 to 0.99). For DUS versus CTA, we found two studies in the range of 70% to 99%; the sensitivity varied from 0.57 to 0.94 and the specificity varied from 0.87 to 0.98. For occlusion, the summary sensitivity was 0.95 (95% CI 0.80 to 0.99) and the summary specificity was 0.91 (95% CI 0.09 to 0.99). For DUS versus MRA, there was one study with results for 50% to 99% carotid artery stenosis, with a sensitivity of 0.88 (95% CI 0.70 to 0.98) and specificity of 0.60 (95% CI 0.15 to 0.95); in the 70% to 99% range, two studies were included, with sensitivity that varied from 0.54 to 0.99 and specificity that varied from 0.78 to 0.89. We could perform only a few of the proposed sensitivity analyses because of the small number of studies included. AUTHORS' CONCLUSIONS: This review provides evidence that the diagnostic accuracy of DUS is high, especially at discriminating between the presence or absence of significant carotid artery stenosis (< 50% or 50% to 99%). This evidence, plus its less invasive nature, supports the early use of DUS for the detection of carotid artery stenosis. The accuracy for 70% to 99% carotid artery stenosis and occlusion is high. Clinicians should exercise caution when using DUS as the single preoperative diagnostic method, and the limitations should be considered. There was little evidence of the accuracy of DUS when compared with CTA or MRA. The results of this review should be interpreted with caution because they are based on studies of low methodological quality, mainly due to the patient selection method. Methodological problems in participant inclusion criteria from the studies discussed above apparently influenced an overestimated estimate of prevalence values. Most of the studies included failed to precisely describe inclusion criteria and previous testing. Future diagnostic accuracy studies should include direct comparisons of the various modalities of diagnostic tests (mainly DUS, CTA, and MRA) for carotid artery stenosis since DSA is no longer considered to be the best method for diagnosing carotid stenosis and less invasive tests are now used as reference standards in clinical practice. Also, for future studies, the participant inclusion criteria require careful attention.

Anticoagulants for people hospitalised with COVID-19.

BACKGROUND: The primary manifestation of coronavirus disease 2019 (COVID-19) is respiratory insufficiency that can also be related to diffuse pulmonary microthrombosis and thromboembolic events, such as pulmonary embolism, deep vein thrombosis, or arterial thrombosis. People with COVID-19 who develop thromboembolism have a worse prognosis. Anticoagulants such as heparinoids (heparins or pentasaccharides), vitamin K antagonists and direct anticoagulants are used for the prevention and treatment of venous or arterial thromboembolism. Besides their anticoagulant properties, heparinoids have an additional anti-inflammatory potential. However, the benefit of anticoagulants for people with COVID-19 is still under debate. OBJECTIVES: To assess the benefits and harms of anticoagulants versus active comparator, placebo or no intervention in people hospitalised with COVID-19. SEARCH METHODS: We searched the CENTRAL, MEDLINE, Embase, LILACS and IBECS databases, the Cochrane COVID-19 Study Register and medRxiv preprint database from their inception to 14 April 2021. We also checked the reference lists of any relevant systematic reviews identified, and contacted specialists in the field for additional references to trials. SELECTION CRITERIA: Eligible studies were randomised controlled trials (RCTs), quasi-RCTs, cluster-RCTs and cohort studies that compared prophylactic anticoagulants versus active comparator, placebo or no intervention for the management of people hospitalised with COVID-19. We excluded studies without a comparator group and with a retrospective design (all previously included studies) as we were able to include better study designs. Primary outcomes were all-cause mortality and necessity for additional respiratory support. Secondary outcomes were mortality related to COVID-19, deep vein thrombosis, pulmonary embolism, major bleeding, adverse events, length of hospital stay and quality of life. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methodological procedures. We used Cochrane RoB 1 to assess the risk of bias for RCTs, ROBINS-I to assess risk of bias for non-randomised studies (NRS) and GRADE to assess the certainty of evidence. We meta-analysed data when appropriate. MAIN RESULTS: We included seven studies (16,185 participants) with participants hospitalised with COVID-19, in either intensive care units, hospital wards or emergency departments. Studies were from Brazil (2), Iran (1), Italy (1), and the USA (1), and two involved more than country. The mean age of participants was 55 to 68 years and the follow-up period ranged from 15 to 90 days. The studies assessed the effects of heparinoids, direct anticoagulants or vitamin K antagonists, and reported sparse data or did not report some of our outcomes of interest: necessity for additional respiratory support, mortality related to COVID-19, and quality of life. Higher-dose versus lower-dose anticoagulants (4 RCTs, 4647 participants) Higher-dose anticoagulants result in little or no difference in all-cause mortality (risk ratio (RR) 1.03, 95% CI 0.92 to 1.16, 4489 participants; 4 RCTs) and increase minor bleeding (RR 3.28, 95% CI 1.75 to 6.14, 1196 participants; 3 RCTs) compared to lower-dose anticoagulants up to 30 days (high-certainty evidence). Higher-dose anticoagulants probably reduce pulmonary embolism (RR 0.46, 95% CI 0.31 to 0.70, 4360 participants; 4 RCTs), and slightly increase major bleeding (RR 1.78, 95% CI 1.13 to 2.80, 4400 participants; 4 RCTs) compared to lower-dose anticoagulants up to 30 days (moderate-certainty evidence). Higher-dose anticoagulants may result in little or no difference in deep vein thrombosis (RR 1.08, 95% CI 0.57 to 2.03, 3422 participants; 4 RCTs), stroke (RR 0.91, 95% CI 0.40 to 2.03, 4349 participants; 3 RCTs), major adverse limb events (RR 0.33, 95% CI 0.01 to 7.99, 1176 participants; 2 RCTs), myocardial infarction (RR 0.86, 95% CI 0.48 to 1.55, 4349 participants; 3 RCTs), atrial fibrillation (RR 0.35, 95% CI 0.07 to 1.70, 562 participants; 1 study), or thrombocytopenia (RR 0.94, 95% CI 0.71 to 1.24, 2789 participants; 2 RCTs) compared to lower-dose anticoagulants up to 30 days (low-certainty evidence). It is unclear whether higher-dose anticoagulants have any effect on necessity for additional respiratory support, mortality related to COVID-19, and quality of life (very low-certainty evidence or no data). Anticoagulants versus no treatment (3 prospective NRS, 11,538 participants) Anticoagulants may reduce all-cause mortality but the evidence is very uncertain due to two study results being at critical and serious risk of bias (RR 0.64, 95% CI 0.55 to 0.74, 8395 participants; 3 NRS; very low-certainty evidence). It is uncertain if anticoagulants have any effect on necessity for additional respiratory support, mortality related to COVID-19, deep vein thrombosis, pulmonary embolism, major bleeding, stroke, myocardial infarction and quality of life (very low-certainty evidence or no data). Ongoing studies We found 62 ongoing studies in hospital settings (60 RCTs, 35,470 participants; 2 prospective NRS, 120 participants) in 20 different countries. Thirty-five ongoing studies plan to report mortality and 26 plan to report necessity for additional respiratory support. We expect 58 studies to be completed in December 2021, and four in July 2022. From 60 RCTs, 28 are comparing different doses of anticoagulants, 24 are comparing anticoagulants versus no anticoagulants, seven are comparing different types of anticoagulants, and one did not report detail of the comparator group. AUTHORS' CONCLUSIONS: When compared to a lower-dose regimen, higher-dose anticoagulants result in little to no difference in all-cause mortality and increase minor bleeding in people hospitalised with COVID-19 up to 30 days. Higher-dose anticoagulants possibly reduce pulmonary embolism, slightly increase major bleeding, may result in little to no difference in hospitalisation time, and may result in little to no difference in deep vein thrombosis, stroke, major adverse limb events, myocardial infarction, atrial fibrillation, or thrombocytopenia.  Compared with no treatment, anticoagulants may reduce all-cause mortality but the evidence comes from non-randomised studies and is very uncertain. It is unclear whether anticoagulants have any effect on the remaining outcomes compared to no anticoagulants (very low-certainty evidence or no data). Although we are very confident that new RCTs will not change the effects of different doses of anticoagulants on mortality and minor bleeding, high-quality RCTs are still needed, mainly for the other primary outcome (necessity for additional respiratory support), the comparison with no anticoagulation, when comparing the types of anticoagulants and giving anticoagulants for a prolonged period of time.

Treatment for telangiectasias and reticular veins.

BACKGROUND: Telangiectasias (spider veins) and reticular veins on the lower limbs are very common, increase with age, and have been found in 41% of women. The cause is unknown and the patients may be asymptomatic or can report pain, burning or itching. Treatments include sclerotherapy, laser, intense pulsed light, microphlebectomy and thermoablation, but none is established as preferable. OBJECTIVES: To assess the effects of sclerotherapy, laser therapy, intensive pulsed light, thermocoagulation, and microphlebectomy treatments for telangiectasias and reticular veins. SEARCH METHODS: The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, AMED and CINAHL databases, and the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 16 March 2021. We undertook additional searches in LILACS and IBECS databases, reference checking, and contacted specialists in the field, manufacturers and study authors to identify additional studies. SELECTION CRITERIA: We included randomised controlled trials (RCTs) and quasi-RCTs that compared treatment methods such as sclerotherapy, laser therapy, intensive pulsed light, thermocoagulation, and microphlebectomy for telangiectasias and reticular veins in the lower limb. We included studies that compared individual treatment methods against placebo, or that compared different sclerosing agents, foam or laser treatment, or that used a combination of treatment methods. DATA COLLECTION AND ANALYSIS: Three review authors independently performed study selection, extracted data, assessed risks of bias and assessed the certainty of evidence using GRADE. The outcomes of interest were resolution or improvement (or both) of telangiectasias, adverse events (including hyperpigmentation, matting), pain, recurrence, time to resolution, and quality of life. MAIN RESULTS: We included 3632 participants from 35 RCTs. Studies compared a variety of sclerosing agents, laser treatment and compression. No studies investigated intensive pulsed light, thermocoagulation or microphlebectomy. None of the included studies assessed recurrence or time to resolution. Overall the risk of bias of the included studies was moderate. We downgraded the certainty of evidence to moderate or low because of clinical heterogeneity and imprecision due to the wide confidence intervals (CIs) and few participants for each comparison. Any sclerosing agent versus placebo There was moderate-certainty evidence that sclerosing agents showed more resolution or improvement of telangiectasias compared to placebo (standard mean difference (SMD) 3.08, 95% CI 2.68 to 3.48; 4 studies, 613 participants/procedures), and more frequent adverse events: hyperpigmentation (risk ratio (RR) 11.88, 95% CI 4.54 to 31.09; 3 studies, 528 participants/procedures); matting (RR 4.06, 95% CI 1.28 to 12.84; 3 studies, 528 participants/procedures). There may be more pain experienced in the sclerosing-agents group compared to placebo (SMD 0.70, 95% CI 0.06 to 1.34; 1 study, 40 participants; low-certainty evidence). Polidocanol versus any sclerosing agent There was no clear difference in resolution or improvement (or both) of telangiectasias (SMD 0.01, 95% CI -0.13 to 0.14; 7 studies, 852 participants/procedures), hyperpigmentation (RR 0.94, 95% CI 0.62 to 1.43; 6 studies, 819 participants/procedures), or matting (RR 0.82, 95% CI 0.52 to 1.27; 7 studies, 859 participants/procedures), but there were fewer cases of pain (SMD -0.26, 95% CI -0.44 to -0.08; 5 studies, 480 participants/procedures) in the polidocanol group. All moderate-certainty evidence. Sodium tetradecyl sulphate (STS) versus any sclerosing agent There was no clear difference in resolution or improvement (or both) of telangiectasias (SMD -0.07, 95% CI -0.25 to 0.11; 4 studies, 473 participants/procedures). There was more hyperpigmentation (RR 1.71, 95% CI 1.10 to 2.64; 4 studies, 478 participants/procedures), matting (RR 2.10, 95% CI 1.14 to 3.85; 2 studies, 323 participants/procedures) and probably more pain (RR 1.49, 95% CI 0.99 to 2.25; 4 studies, 409 participants/procedures). All moderate-certainty evidence. Foam versus any sclerosing agent There was no clear difference in resolution or improvement (or both) of telangiectasias (SMD 0.04, 95% CI -0.26 to 0.34; 2 studies, 187 participants/procedures); hyperpigmentation (RR 2.12, 95% CI 0.44 to 10.23; 2 studies, 187 participants/procedures) or pain (SMD -0.10, 95% CI -0.44 to 0.24; 1 study, 147 participants/procedures). There may be more matting using foam (RR 6.12, 95% CI 1.04 to 35.98; 2 studies, 187 participants/procedures). All low-certainty evidence. Laser versus any sclerosing agent There was no clear difference in resolution or improvement (or both) of telangiectasias (SMD -0.09, 95% CI -0.25 to 0.07; 5 studies, 593 participants/procedures), or matting (RR 1.00, 95% CI 0.46 to 2.19; 2 studies, 162 participants/procedures), and maybe less hyperpigmentation (RR 0.57, 95% CI 0.40 to 0.80; 4 studies, 262 participants/procedures) in the laser group. All moderate-certainty evidence. High heterogeneity of the studies reporting on pain prevented pooling, and results were inconsistent (low-certainty evidence). Laser plus sclerotherapy (polidocanol) versus sclerotherapy (polidocanol) Low-certainty evidence suggests there may be more resolution or improvement (or both) of telangiectasias in the combined group (SMD 5.68, 95% CI 5.14 to 6.23; 2 studies, 710 participants), and no clear difference in hyperpigmentation (RR 0.83, 95% CI 0.35 to 1.99; 2 studies, 656 participants) or matting (RR 0.83, 95% CI 0.21 to 3.28; 2 studies, 656 participants). There may be more pain in the combined group (RR 2.44, 95% CI 1.69 to 3.55; 1 study, 596 participants; low-certainty evidence). AUTHORS' CONCLUSIONS: Small numbers of studies and participants in each comparison limited our confidence in the evidence. Sclerosing agents were more effective than placebo for resolution or improvement of telangiectasias but also caused more adverse events (moderate-certainty evidence), and may result in more pain (low-certainty evidence). There was no evidence of a benefit in resolution or improvement for any sclerosant compared to another or to laser. There may be more resolution or improvement of telangiectasias in the combined laser and polidocanol group compared to polidocanol alone (low-certainty evidence). There may be differences between treatments in adverse events and pain. Compared to other sclerosing agents polidocanol probably causes less pain; STS resulted in more hyperpigmentation, matting and probably pain; foam may cause more matting (low-certainty evidence); laser treatment may result in less hyperpigmentation (moderate-certainty evidence). Further well-designed studies are required to provide evidence for other available treatments and important outcomes (such as recurrence, time to resolution and delayed adverse events); and to improve our confidence in the identified comparisons.

Ultrasound guidance for arterial (other than femoral) catheterisation in adults.

BACKGROUND: Arterial vascular access is a frequently performed procedure, with a high possibility for adverse events (e.g. pneumothorax, haemothorax, haematoma, amputation, death), and additional techniques such as ultrasound may be useful for improving outcomes. However, ultrasound guidance for arterial access in adults is still under debate. OBJECTIVES: To assess the effects of ultrasound guidance for arterial (other than femoral) catheterisation in adults. SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase, LILACS, and CINAHL on 21 May 2021. We also searched IBECS, WHO ICTRP, and ClinicalTrials.gov on 16 June 2021, and we checked the reference lists of retrieved articles. SELECTION CRITERIA: Randomised controlled trials (RCTs), including cross-over trials and cluster-RCTs, comparing ultrasound guidance, alone or associated with other forms of guidance, versus other interventions or palpation and landmarks for arterial (other than femoral) guidance in adults. DATA COLLECTION AND ANALYSIS: Two review authors independently performed study selection, extracted data, assessed risk of bias, and assessed the certainty of evidence using GRADE. MAIN RESULTS: We included 48 studies (7997 participants) that tested palpation and landmarks, Doppler auditory ultrasound assistance (DUA), direct ultrasound guidance with B-mode, or any other modified ultrasound technique for arterial (axillary, dorsalis pedis, and radial) catheterisation in adults. Radial artery Real-time B-mode ultrasound versus palpation and landmarks Real-time B-mode ultrasound guidance may improve first attempt success rate (risk ratio (RR) 1.44, 95% confidence interval (CI) 1.29 to 1.61; 4708 participants, 27 studies; low-certainty evidence) and overall success rate (RR 1.11, 95% CI 1.06 to 1.16; 4955 participants, 28 studies; low-certainty evidence), and may decrease time needed for a successful procedure (mean difference (MD) -0.33 minutes, 95% CI -0.54 to -0.13; 4902 participants, 26 studies; low-certainty evidence) up to one hour compared to palpation and landmarks. Real-time B-mode ultrasound guidance probably decreases major haematomas (RR 0.35, 95% CI 0.23 to 0.56; 2504 participants, 16 studies; moderate-certainty evidence). It is uncertain whether real-time B-mode ultrasound guidance has any effect on pseudoaneurysm, pain, and quality of life (QoL) compared to palpation and landmarks (very low-certainty evidence). Real-time B-mode ultrasound versus DUA One study (493 participants) showed that real-time B-mode ultrasound guidance probably improves first attempt success rate (RR 1.35, 95% CI 1.11 to 1.64; moderate-certainty evidence) and time needed for a successful procedure (MD -1.57 minutes, 95% CI -1.78 to -1.36; moderate-certainty evidence) up to 72 hours compared to DUA. Real-time B-mode ultrasound guidance may improve overall success rate (RR 1.13, 95% CI 0.99 to 1.29; low-certainty evidence) up to 72 hours compared to DUA. Pseudoaneurysm, major haematomas, pain, and QoL were not reported. Real-time B-mode ultrasound versus modified real-time B-mode ultrasound Real-time B-mode ultrasound guidance may decrease first attempt success rate (RR 0.68, 95% CI 0.55 to 0.84; 153 participants, 2 studies; low-certainty evidence), may decrease overall success rate (RR 0.93, 95% CI 0.86 to 1.01; 153 participants, 2 studies; low-certainty evidence), and may lead to no difference in time needed for a successful procedure (MD 0.04 minutes, 95% CI -0.01 to 0.09; 153 participants, 2 studies; low-certainty evidence) up to one hour compared to modified real-time B-mode ultrasound guidance. It is uncertain whether real-time B-mode ultrasound guidance has any effect on major haematomas compared to modified real-time B-mode ultrasound (very low-certainty evidence). Pseudoaneurysm, pain, and QoL were not reported. In-plane versus out-of-plane B-mode ultrasound In-plane real-time B-mode ultrasound guidance may lead to no difference in overall success rate (RR 1.00, 95% CI 0.96 to 1.05; 1051 participants, 8 studies; low-certainty evidence) and in time needed for a successful procedure (MD -0.06 minutes, 95% CI -0.16 to 0.05; 1134 participants, 9 studies; low-certainty evidence) compared to out-of-plane B-mode ultrasound up to one hour. It is uncertain whether in-plane real-time B-mode ultrasound guidance has any effect on first attempt success rate or major haematomas compared to out-of-plane B-mode ultrasound (very low-certainty evidence). Pseudoaneurysm, pain, and QoL were not reported. DUA versus palpation and landmarks DUA may lead to no difference in first attempt success rate (RR 1.01, 95% CI 0.90 to 1.14; 666 participants, 2 studies; low-certainty evidence) or overall success rate (RR 0.99, 95% CI 0.92 to 1.07; 666 participants, 2 studies; low-certainty evidence) and probably increases time needed for a successful procedure (MD 0.45 minutes, 95% CI 0.20 to 0.70; 500 participants, 1 study; moderate-certainty evidence) up to 72 hours compared to palpation and landmarks. Pseudoaneurysm, major haematomas, pain, and QoL were not reported. Oblique-axis versus long-axis in-plane B-mode ultrasound Oblique-axis in-plane B-mode ultrasound guidance may increase overall success rate (RR 1.27, 95% CI 1.05 to 1.53; 215 participants, 2 studies; low-certainty evidence) up to 72 hours compared to long-axis in-plane B-mode ultrasound. It is uncertain whether oblique-axis in-plane B-mode ultrasound guidance has any effect on first attempt success rate, time needed for a successful procedure, and major haematomas compared to long-axis in-plane B-mode ultrasound. Pseudoaneurysm, pain, and QoL were not reported. We are uncertain about effects in the following comparisons due to very low-certainty evidence and unreported outcomes: real-time B-mode ultrasound versus palpation and landmarks (axillary and dorsalis pedis arteries), real-time B-mode ultrasound versus near-infrared laser (radial artery), and dynamic versus static out-of-plane B-mode ultrasound (radial artery). AUTHORS' CONCLUSIONS: Real-time B-mode ultrasound guidance may improve first attempt success rate, overall success rate, and time needed for a successful procedure for radial artery catheterisation compared to palpation, or DUA. In addition, real-time B-mode ultrasound guidance probably decreases major haematomas compared to palpation. However, we are uncertain about the evidence on major haematomas and pain for other comparisons due to very low-certainty evidence and unreported outcomes. We are also uncertain about the effects on pseudoaneurysm and QoL for axillary and dorsalis pedis arteries catheterisation. Given that first attempt success rate and pseudoaneurysm are the most relevant outcomes for people who underwent arterial catheterisation, future studies must measure both. Future trials must be large enough to detect effects, use validated scales, and report longer-term follow-up.

Complementary and alternative therapies for post-caesarean pain.

BACKGROUND: Pain after caesarean sections (CS) can affect the well-being of the mother and her ability with her newborn. Conventional pain-relieving strategies are often underused because of concerns about the adverse maternal and neonatal effects. Complementary alternative therapies (CAM) may offer an alternative for post-CS pain. OBJECTIVES: To assess the effects of CAM for post-caesarean pain. SEARCH METHODS: We searched Cochrane Pregnancy and Childbirth's Trials Register, LILACS, PEDro, CAMbase, ClinicalTrials.gov and the WHO International Clinical Trials Registry Platform (ICTRP) (6 September 2019), and checked the reference lists of retrieved articles. SELECTION CRITERIA: Randomised controlled trials (RCTs), including quasi-RCTs and cluster-RCTs, comparing CAM, alone or associated with other forms of pain relief, versus other treatments or placebo or no treatment, for the treatment of post-CS pain. DATA COLLECTION AND ANALYSIS: Two review authors independently performed study selection, extracted data, assessed risk of bias and assessed the certainty of evidence using GRADE. MAIN RESULTS: We included 37 studies (3076 women) which investigated eight different CAM therapies for post-CS pain relief. There is substantial heterogeneity among the trials. We downgraded the certainty of evidence due to small numbers of women participating in the trials and to risk of bias related to lack of blinding and inadequate reporting of randomisation processes. None of the trials reported pain at six weeks after discharge. Primary outcomes were pain and adverse effects, reported per intervention below. Secondary outcomes included vital signs, rescue analgesic requirement at six weeks after discharge; all of which were poorly reported, not reported, or we are uncertain as to the effect Acupuncture or acupressure We are very uncertain if acupuncture or acupressure (versus no treatment) or acupuncture or acupressure plus analgesia (versus placebo plus analgesia) has any effect on pain because the quality of evidence is very low. Acupuncture or acupressure plus analgesia (versus analgesia) may reduce pain at 12 hours (standardised mean difference (SMD) -0.28, 95% confidence interval (CI) -0.64 to 0.07; 130 women; 2 studies; low-certainty evidence) and 24 hours (SMD -0.63, 95% CI -0.99 to -0.26; 2 studies; 130 women; low-certainty evidence). It is uncertain whether acupuncture or acupressure (versus no treatment) or acupuncture or acupressure plus analgesia (versus analgesia) has any effect on the risk of adverse effects because the quality of evidence is very low. Aromatherapy Aromatherapy plus analgesia may reduce pain when compared with placebo plus analgesia at 12 hours (mean difference (MD) -2.63 visual analogue scale (VAS), 95% CI -3.48 to -1.77; 3 studies; 360 women; low-certainty evidence) and 24 hours (MD -3.38 VAS, 95% CI -3.85 to -2.91; 1 study; 200 women; low-certainty evidence). We are uncertain if aromatherapy plus analgesia has any effect on adverse effects (anxiety) compared with placebo plus analgesia. Electromagnetic therapy Electromagnetic therapy may reduce pain compared with placebo plus analgesia at 12 hours (MD -8.00, 95% CI -11.65 to -4.35; 1 study; 72 women; low-certainty evidence) and 24 hours (MD -13.00 VAS, 95% CI -17.13 to -8.87; 1 study; 72 women; low-certainty evidence). Massage We identified six studies (651 women), five of which were quasi-RCTs, comparing massage (foot and hand) plus analgesia versus analgesia. All the evidence relating to pain, adverse effects (anxiety), vital signs and rescue analgesic requirement was very low-certainty. Music Music plus analgesia may reduce pain when compared with placebo plus analgesia at one hour (SMD -0.84, 95% CI -1.23 to -0.46; participants = 115; studies = 2; I2 = 0%; low-certainty evidence), 24 hours (MD -1.79, 95% CI -2.67 to -0.91; 1 study; 38 women; low-certainty evidence), and also when compared with analgesia at one hour (MD -2.11, 95% CI -3.11 to -1.10; 1 study; 38 women; low-certainty evidence) and at 24 hours (MD -2.69, 95% CI -3.67 to -1.70; 1 study; 38 women; low-certainty evidence). It is uncertain whether music plus analgesia has any effect on adverse effects (anxiety), when compared with placebo plus analgesia because the quality of evidence is very low. Reiki We are uncertain if Reiki plus analgesia compared with analgesia alone has any effect on pain, adverse effects, vital signs or rescue analgesic requirement because the quality of evidence is very low (one study, 90 women). Relaxation Relaxation may reduce pain compared with standard care at 24 hours (MD -0.53 VAS, 95% CI -1.05 to -0.01; 1 study; 60 women; low-certainty evidence). Transcutaneous electrical nerve stimulation TENS (versus no treatment) may reduce pain at one hour (MD -2.26, 95% CI -3.35 to -1.17; 1 study; 40 women; low-certainty evidence). TENS plus analgesia (versus placebo plus analgesia) may reduce pain compared with placebo plus analgesia at one hour (SMD -1.10 VAS, 95% CI -1.37 to -0.82; 3 studies; 238 women; low-certainty evidence) and at 24 hours (MD -0.70 VAS, 95% CI -0.87 to -0.53; 108 women; 1 study; low-certainty evidence). TENS plus analgesia (versus placebo plus analgesia) may reduce heart rate (MD -7.00 bpm, 95% CI -7.63 to -6.37; 108 women; 1 study; low-certainty evidence) and respiratory rate (MD -1.10 brpm, 95% CI -1.26 to -0.94; 108 women; 1 study; low-certainty evidence). We are uncertain if TENS plus analgesia (versus analgesia) has any effect on pain at six hours or 24 hours, or vital signs because the quality of evidence is very low (two studies, 92 women). AUTHORS' CONCLUSIONS: Some CAM therapies may help reduce post-CS pain for up to 24 hours. The evidence on adverse events is too uncertain to make any judgements on safety and we have no evidence about the longer-term effects on pain. Since pain control is the most relevant outcome for post-CS women and their clinicians, it is important that future studies of CAM for post-CS pain measure pain as a primary outcome, preferably as the proportion of participants with at least moderate (30%) or substantial (50%) pain relief. Measuring pain as a dichotomous variable would improve the certainty of evidence and it is easy to understand for non-specialists. Future trials also need to be large enough to detect effects on clinical outcomes; measure other important outcomes as listed lin this review, and use validated scales.

Internal iliac artery revascularisation versus internal iliac artery occlusion for endovascular treatment of aorto-iliac aneurysms.

BACKGROUND: Endovascular aortic aneurysm repair (EVAR) is used to treat aorto-iliac and isolated iliac aneurysms in selected patients, and prospective studies have shown advantages compared with open surgical repair, mainly in the first years of follow-up. Although this technique produces good results, anatomic issues (such as common iliac artery ectasia or an aneurysm that involves the iliac bifurcation) can make EVAR more complex and challenging and can lead to an inadequate distal seal zone for the stent-graft. Inadequate distal fixation in the common iliac arteries can lead to a type Ib endoleak. To avoid this complication, one of the most commonly used techniques is unilateral or bilateral internal iliac artery occlusion and extension of the iliac limb stent-graft to the external iliac arteries with or without embolisation of the internal iliac artery. However, this occlusion is not without harm and is associated with ischaemic complications in the pelvic territory such as buttock claudication, sexual dysfunction, ischaemic colitis, gluteal necrosis, and spinal cord injury. New endovascular devices and alternative techniques such as iliac branch devices and the sandwich technique have been described to maintain pelvic perfusion and decrease complications, achieving revascularisation of the internal iliac arteries in patients not suitable for an adequate seal zone in the common iliac arteries. These approaches may also preserve the quality of life of treated individuals and may decrease other serious complications including spinal cord ischaemia, ischaemic colitis, and gluteal necrosis, thereby decreasing the morbidity and mortality of EVAR. OBJECTIVES: To assess the effects of internal iliac artery revascularisation versus internal iliac artery occlusion during endovascular repair of aorto-iliac aneurysms and isolated iliac aneurysms involving the iliac bifurcation. SEARCH METHODS: The Cochrane Vascular Information Specialists searched the Cochrane Vascular Specialised Register; the Cochrane Central Register of Controlled Trials (CENTRAL), in the Cochrane Library; MEDLINE; Embase; the Cumulative Index to Nursing and Allied Health Literature (CINAHL); and the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 28 August 2019. The review authors searched Latin American Caribbean Health Sciences Literature (LILACS) and the Indice Bibliográfico Español de Ciencias de la Salud (IBECS) on 28 August 2019 and contacted specialists in the field and manufacturers to identify relevant studies. SELECTION CRITERIA: We planned to include all randomised controlled trials (RCTs) that compared internal iliac artery revascularisation with internal iliac artery occlusion for patients undergoing endovascular treatment of aorto-iliac aneurysms and isolated iliac aneurysms involving the iliac bifurcation. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed identified studies for potential inclusion in the review. We used standard methodological procedures in accordance with the Cochrane Handbook for Systematic Review of Interventions. MAIN RESULTS: We identified no RCTs that met the inclusion criteria. AUTHORS' CONCLUSIONS: We found no RCTs that compared internal iliac artery revascularisation versus internal iliac artery occlusion for endovascular treatment of aorto-iliac aneurysms and isolated iliac aneurysms involving the iliac bifurcation. High-quality studies that evaluate the best strategy for managing endovascular repair of aorto-iliac aneurysms with inadequate distal seal zones in the common iliac artery are needed.

Prophylactic anticoagulants for people hospitalised with COVID-19.

BACKGROUND: Coronavirus disease 2019 (COVID-19) is a serious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The primary manifestation is respiratory insufficiency that can also be related to diffuse pulmonary microthrombosis in people with COVID-19. This disease also causes thromboembolic events, such as pulmonary embolism, deep venous thrombosis, arterial thrombosis, catheter thrombosis, and disseminated intravascular coagulopathy. Recent studies have indicated a worse prognosis for people with COVID-19 who developed thromboembolism. Anticoagulants are medications used in the prevention and treatment of venous or arterial thromboembolic events. Several drugs are used in the prophylaxis and treatment of thromboembolic events, such as heparinoids (heparins or pentasaccharides), vitamin K antagonists and direct anticoagulants. Besides their anticoagulant properties, heparinoids have an additional anti-inflammatory potential, that may affect the clinical evolution of people with COVID-19. Some practical guidelines address the use of anticoagulants for thromboprophylaxis in people with COVID-19, however, the benefit of anticoagulants for people with COVID-19 is still under debate. OBJECTIVES: To assess the effects of prophylactic anticoagulants versus active comparator, placebo or no intervention, on mortality and the need for respiratory support in people hospitalised with COVID-19. SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase, LILACS and IBECS databases, the Cochrane COVID-19 Study Register and medRxiv preprint database from their inception to 20 June 2020. We also checked reference lists of any relevant systematic reviews identified and contacted specialists in the field for additional references to trials. SELECTION CRITERIA: Randomised controlled trials (RCTs), quasi-RCTs, cluster-RCTs and cohort studies that compared prophylactic anticoagulants (heparin, vitamin K antagonists, direct anticoagulants, and pentasaccharides) versus active comparator, placebo or no intervention for the management of people hospitalised with COVID-19. We excluded studies without a comparator group. Primary outcomes were all-cause mortality and need for additional respiratory support. Secondary outcomes were mortality related to COVID-19, deep vein thrombosis (DVT), pulmonary embolism, major bleeding, adverse events, length of hospital stay and quality of life. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methodological procedures. We used ROBINS-I to assess risk of bias for non-randomised studies (NRS) and GRADE to assess the certainty of evidence. We reported results narratively. MAIN RESULTS: We identified no RCTs or quasi-RCTs that met the inclusion criteria. We included seven retrospective NRS (5929 participants), three of which were available as preprints. Studies were conducted in China, Italy, Spain and the USA. All of the studies included people hospitalised with COVID-19, in either intensive care units, hospital wards or emergency departments. The mean age of participants (reported in 6 studies) ranged from 59 to 72 years. Only three included studies reported the follow-up period, which varied from 8 to 35 days. The studies did not report on most of our outcomes of interest: need for additional respiratory support, mortality related to COVID-19, DVT, pulmonary embolism, adverse events, and quality of life. Anticoagulants (all types) versus no treatment (6 retrospective NRS, 5685 participants) One study reported a reduction in all-cause mortality (adjusted odds ratio (OR) 0.42, 95% confidence interval (CI) 0.26 to 0.66; 2075 participants). One study reported a reduction in mortality only in a subgroup of 395 people who required mechanical ventilation (hazard ratio (HR) 0.86, 95% CI 0.82 to 0.89). Three studies reported no differences in mortality (adjusted OR 1.64, 95% CI 0.92 to 2.92; 449 participants; unadjusted OR 1.66, 95% CI 0.76 to 3.64; 154 participants and adjusted risk ratio (RR) 1.15, 95% CI 0.29 to 2.57; 192 participants). One study reported zero events in both intervention groups (42 participants). The overall risk of bias for all-cause mortality was critical and the certainty of the evidence was very low. One NRS reported bleeding events in 3% of the intervention group and 1.9% of the control group (OR 1.62, 95% CI 0.96 to 2.71; 2773 participants; low-certainty evidence). Therapeutic-dose anticoagulants versus prophylactic-dose anticoagulants (1 retrospective NRS, 244 participants) The study reported a reduction in all-cause mortality (adjusted HR 0.21, 95% CI 0.10 to 0.46) and a lower absolute rate of death in the therapeutic group (34.2% versus 53%). The overall risk of bias for all-cause mortality was serious and the certainty of the evidence was low. The study also reported bleeding events in 31.7% of the intervention group and 20.5% of the control group (OR 1.8, 95% CI 0.96 to 3.37; low-certainty evidence). Ongoing studies We found 22 ongoing studies in hospital settings (20 RCTs, 14,730 participants; 2 NRS, 997 participants) in 10 different countries (Australia (1), Brazil (1), Canada (2), China (3), France (2), Germany (1), Italy (4), Switzerland (1), UK (1) and USA (6)). Twelve ongoing studies plan to report mortality and six plan to report additional respiratory support. Thirteen studies are expected to be completed in December 2020 (6959 participants), eight in July 2021 (8512 participants), and one in December 2021 (256 participants). Four of the studies plan to include 1000 participants or more. AUTHORS' CONCLUSIONS: There is currently insufficient evidence to determine the risks and benefits of prophylactic anticoagulants for people hospitalised with COVID-19. Since there are 22 ongoing studies that plan to evaluate more than 15,000 participants in this setting, we will add more robust evidence to this review in future updates.

Acetyl-L-carnitine for the treatment of diabetic peripheral neuropathy.

BACKGROUND: Diabetic peripheral neuropathy (DPN) is a common and severe complication that affects 50% of people with diabetes. Painful DPN is reported to occur in 16% to 24% of people with diabetes. A complete and comprehensive management strategy for the prevention and treatment of DPN, whether painful or not, has not yet been defined.Research into treatment for DPN has been characterised by a series of failed clinical trials, with few noteworthy advances. Strategies that support peripheral nerve regeneration and restore neurological function in people with painful or painless DPN are needed. The amino acid acetyl-L-carnitine (ALC) plays a role in the transfer of long-chain fatty acids into mitochondria for ß-oxidation. ALC supplementation also induces neuroprotective and neurotrophic effects in the peripheral nervous system. Therefore, ALC supplementation targets several mechanisms relevant to potential nerve repair and regeneration, and could have clinical therapeutic potential. There is a need for a systematic review of the evidence from clinical trials. OBJECTIVES: To assess the effects of ALC for the treatment of DPN. SEARCH METHODS: On 2 July 2018, we searched the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, Embase, LILACS, ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform. We checked references, searched citations, and contacted study authors to identify additional studies. SELECTION CRITERIA: We included randomised controlled trials (RCTs) and quasi-RCTs of ALC compared with placebo, other therapy, or no intervention in the treatment of DPN. Participants could be of any sex and age, and have type 1 or type 2 diabetes mellitus, of any severity, with painful or painless DPN. We accepted any definition of minimum criteria for DPN, in accordance with the Toronto Consensus. We imposed no language restriction.Pain was the primary outcome, measured as the proportion of participants with at least 30% (moderate) or 50% (substantial) decrease in pain over baseline, or as the score on a visual analogue scale (VAS) or Likert scale for pain. DATA COLLECTION AND ANALYSIS: We followed standard Cochrane methods. MAIN RESULTS: We included four studies with 907 participants, which were reported in three publications. Three trials studied ALC versus placebo (675 participants); in one trial the dose of ALC was 2000 mg/day, and in the other two trials, it was 1500 mg/day or 3000 mg/day. The fourth trial studied ALC 1500 mg/day versus methylcobalamin 1.5 mg/day (232 participants). The risk of bias was high in both trials of different ALC doses and low in the other two trials.No included trial measured the proportion of participants with at least moderate (30%) or substantial (50%) pain relief. ALC reduced pain more than placebo, measured on a 0- to 100-mm VAS (MD -9.16, 95% CI -16.76 to -1.57; three studies; 540 participants; P = 0.02; I² = 56%; random-effects; very low-certainty evidence; a higher score indicating more pain). At doses of 1500 mg/day or less, the VAS score after ALC treatment was little different from placebo (MD -0.05, 95% CI -10.00 to 9.89; two studies; 159 participants; P = 0.99; I² = 0%), but at doses greater than 1500 mg/day, ALC reduced pain more than placebo (MD -14.93, 95% CI -19.16 to -10.70; three studies; 381 participants; P < 0.00001; I² = 0%). This subgroup analysis should be viewed with caution as the evidence was even less certain than the overall analysis, which was already of very low certainty.Two placebo-controlled studies reported that vibration perception improved after 12 months. We graded this evidence as very low certainty, due to inconsistency and a high risk of bias, as the trial authors did not provide any numerical data. The placebo-controlled studies did not measure functional impairment and disability scores. No study used validated symptom scales. One study performed sensory testing, but the evidence was very uncertain.The fourth included study compared ALC with methylcobalamin, but did not report effects on pain. There was a reduction from baseline to 24 weeks in functional impairment and disability, based on the change in mean Neuropathy Disability Score (NDS; scale from zero to 10), but there was no important difference between the ALC group (mean score 1.66 ± 1.90) and the methylcobalamin group (mean score 1.35 ± 1.65) groups (P = 0.23; low-certainty evidence).One placebo-controlled study reported that six of 147 participants in the ALC > 1500 mg/day group (4.1%) and two of 147 participants in the placebo group (1.4%) discontinued treatment because of adverse events (headache, facial paraesthesia, and gastrointestinal disorders) (P = 0.17). The other two placebo-controlled studies reported no dropouts due to adverse events, and more pain, paraesthesia, and hyperaesthesias in the placebo group than the 3000 mg/day ALC group, but provided no numerical data. The overall certainty of adverse event evidence for the comparison of ALC versus placebo was low.The study comparing ALC with methylcobalamin reported that 34/117 participants (29.1%) experienced adverse events in the ALC group versus 33/115 (28.7%) in the methylcobalamin group (P = 0.95). Nine participants discontinued treatment due to adverse events (ALC: 4 participants, methylcobalamin: 5 participants), which were most commonly gastrointestinal symptoms. The certainty of the adverse event evidence for ALC versus methylcobalamin was low.Two studies were funded by the manufacturer of ALC and the other two studies had at least one co-author who was a consultant for an ALC manufacturer. AUTHORS' CONCLUSIONS: We are very uncertain whether ALC causes a reduction in pain after 6 to 12 months' treatment in people with DPN, when compared with placebo, as the evidence is sparse and of low certainty. Data on functional and sensory impairment and symptoms are lacking, or of very low certainty. The evidence on adverse events is too uncertain to make any judgements on safety.