RESUMEN
Evidence-informed policy-making benefitted from much-needed attention and resources during the COVID-19 pandemic (1). As a result, 3 key movements and innovations are now making it possible to provide better evidence support (higher quality and more aligned to the speed of advisory and decision-making) for policy-making than ever.
Asunto(s)
COVID-19 , Toma de Decisiones , Humanos , Política de Salud , Pandemias , Formulación de PolíticasRESUMEN
BACKGROUND: Viral epidemics or pandemics of acute respiratory infections (ARIs) pose a global threat. Examples are influenza (H1N1) caused by the H1N1pdm09 virus in 2009, severe acute respiratory syndrome (SARS) in 2003, and coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 in 2019. Antiviral drugs and vaccines may be insufficient to prevent their spread. This is an update of a Cochrane Review last published in 2020. We include results from studies from the current COVID-19 pandemic. OBJECTIVES: To assess the effectiveness of physical interventions to interrupt or reduce the spread of acute respiratory viruses. SEARCH METHODS: We searched CENTRAL, PubMed, Embase, CINAHL, and two trials registers in October 2022, with backwards and forwards citation analysis on the new studies. SELECTION CRITERIA: We included randomised controlled trials (RCTs) and cluster-RCTs investigating physical interventions (screening at entry ports, isolation, quarantine, physical distancing, personal protection, hand hygiene, face masks, glasses, and gargling) to prevent respiratory virus transmission. DATA COLLECTION AND ANALYSIS: We used standard Cochrane methodological procedures. MAIN RESULTS: We included 11 new RCTs and cluster-RCTs (610,872 participants) in this update, bringing the total number of RCTs to 78. Six of the new trials were conducted during the COVID-19 pandemic; two from Mexico, and one each from Denmark, Bangladesh, England, and Norway. We identified four ongoing studies, of which one is completed, but unreported, evaluating masks concurrent with the COVID-19 pandemic. Many studies were conducted during non-epidemic influenza periods. Several were conducted during the 2009 H1N1 influenza pandemic, and others in epidemic influenza seasons up to 2016. Therefore, many studies were conducted in the context of lower respiratory viral circulation and transmission compared to COVID-19. The included studies were conducted in heterogeneous settings, ranging from suburban schools to hospital wards in high-income countries; crowded inner city settings in low-income countries; and an immigrant neighbourhood in a high-income country. Adherence with interventions was low in many studies. The risk of bias for the RCTs and cluster-RCTs was mostly high or unclear. Medical/surgical masks compared to no masks We included 12 trials (10 cluster-RCTs) comparing medical/surgical masks versus no masks to prevent the spread of viral respiratory illness (two trials with healthcare workers and 10 in the community). Wearing masks in the community probably makes little or no difference to the outcome of influenza-like illness (ILI)/COVID-19 like illness compared to not wearing masks (risk ratio (RR) 0.95, 95% confidence interval (CI) 0.84 to 1.09; 9 trials, 276,917 participants; moderate-certainty evidence. Wearing masks in the community probably makes little or no difference to the outcome of laboratory-confirmed influenza/SARS-CoV-2 compared to not wearing masks (RR 1.01, 95% CI 0.72 to 1.42; 6 trials, 13,919 participants; moderate-certainty evidence). Harms were rarely measured and poorly reported (very low-certainty evidence). N95/P2 respirators compared to medical/surgical masks We pooled trials comparing N95/P2 respirators with medical/surgical masks (four in healthcare settings and one in a household setting). We are very uncertain on the effects of N95/P2 respirators compared with medical/surgical masks on the outcome of clinical respiratory illness (RR 0.70, 95% CI 0.45 to 1.10; 3 trials, 7779 participants; very low-certainty evidence). N95/P2 respirators compared with medical/surgical masks may be effective for ILI (RR 0.82, 95% CI 0.66 to 1.03; 5 trials, 8407 participants; low-certainty evidence). Evidence is limited by imprecision and heterogeneity for these subjective outcomes. The use of a N95/P2 respirators compared to medical/surgical masks probably makes little or no difference for the objective and more precise outcome of laboratory-confirmed influenza infection (RR 1.10, 95% CI 0.90 to 1.34; 5 trials, 8407 participants; moderate-certainty evidence). Restricting pooling to healthcare workers made no difference to the overall findings. Harms were poorly measured and reported, but discomfort wearing medical/surgical masks or N95/P2 respirators was mentioned in several studies (very low-certainty evidence). One previously reported ongoing RCT has now been published and observed that medical/surgical masks were non-inferior to N95 respirators in a large study of 1009 healthcare workers in four countries providing direct care to COVID-19 patients. Hand hygiene compared to control Nineteen trials compared hand hygiene interventions with controls with sufficient data to include in meta-analyses. Settings included schools, childcare centres and homes. Comparing hand hygiene interventions with controls (i.e. no intervention), there was a 14% relative reduction in the number of people with ARIs in the hand hygiene group (RR 0.86, 95% CI 0.81 to 0.90; 9 trials, 52,105 participants; moderate-certainty evidence), suggesting a probable benefit. In absolute terms this benefit would result in a reduction from 380 events per 1000 people to 327 per 1000 people (95% CI 308 to 342). When considering the more strictly defined outcomes of ILI and laboratory-confirmed influenza, the estimates of effect for ILI (RR 0.94, 95% CI 0.81 to 1.09; 11 trials, 34,503 participants; low-certainty evidence), and laboratory-confirmed influenza (RR 0.91, 95% CI 0.63 to 1.30; 8 trials, 8332 participants; low-certainty evidence), suggest the intervention made little or no difference. We pooled 19 trials (71, 210 participants) for the composite outcome of ARI or ILI or influenza, with each study only contributing once and the most comprehensive outcome reported. Pooled data showed that hand hygiene may be beneficial with an 11% relative reduction of respiratory illness (RR 0.89, 95% CI 0.83 to 0.94; low-certainty evidence), but with high heterogeneity. In absolute terms this benefit would result in a reduction from 200 events per 1000 people to 178 per 1000 people (95% CI 166 to 188). Few trials measured and reported harms (very low-certainty evidence). We found no RCTs on gowns and gloves, face shields, or screening at entry ports. AUTHORS' CONCLUSIONS: The high risk of bias in the trials, variation in outcome measurement, and relatively low adherence with the interventions during the studies hampers drawing firm conclusions. There were additional RCTs during the pandemic related to physical interventions but a relative paucity given the importance of the question of masking and its relative effectiveness and the concomitant measures of mask adherence which would be highly relevant to the measurement of effectiveness, especially in the elderly and in young children. There is uncertainty about the effects of face masks. The low to moderate certainty of evidence means our confidence in the effect estimate is limited, and that the true effect may be different from the observed estimate of the effect. The pooled results of RCTs did not show a clear reduction in respiratory viral infection with the use of medical/surgical masks. There were no clear differences between the use of medical/surgical masks compared with N95/P2 respirators in healthcare workers when used in routine care to reduce respiratory viral infection. Hand hygiene is likely to modestly reduce the burden of respiratory illness, and although this effect was also present when ILI and laboratory-confirmed influenza were analysed separately, it was not found to be a significant difference for the latter two outcomes. Harms associated with physical interventions were under-investigated. There is a need for large, well-designed RCTs addressing the effectiveness of many of these interventions in multiple settings and populations, as well as the impact of adherence on effectiveness, especially in those most at risk of ARIs.
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Control de Enfermedades Transmisibles , Infecciones del Sistema Respiratorio , Anciano , Preescolar , Humanos , COVID-19/prevención & control , COVID-19/epidemiología , Gripe Humana/epidemiología , Gripe Humana/prevención & control , Infecciones del Sistema Respiratorio/epidemiología , Infecciones del Sistema Respiratorio/prevención & control , SARS-CoV-2 , Ensayos Clínicos Controlados Aleatorios como Asunto , Subtipo H1N1 del Virus de la Influenza A , Control de Enfermedades Transmisibles/métodos , Salud Global/estadística & datos numéricosRESUMEN
CLINICAL QUESTION: In adults with low density lipoprotein (LDL) cholesterol levels >1.8 mmol/L (>70 mg/dL) who are already taking the maximum dose of statins or are intolerant to statins, should another lipid-lowering drug be added, either a proprotein convertase subtilisin/kexin 9 (PCSK9) inhibitor or ezetimibe, to reduce the risk of major cardiovascular events? If so, which drug is preferred? Having decided to use one, should we add the other lipid-lowering drug? CURRENT PRACTICE: Most guidelines emphasise LDL cholesterol targets in their recommendations for prescribing PCSK9 inhibitors and/or ezetimibe in adults at high risk of experiencing a major adverse cardiovascular event. However, to achieve these goals in very high risk patients with statins alone is almost impossible, so physicians are increasingly considering other lipid-lowering drugs solely for achieving LDL cholesterol treatment goals rather than for achieving important absolute cardiovascular risk reduction. Most guidelines do not systematically assess the cardiovascular benefits of adding PCSK9 inhibitors and/or ezetimibe for all risk groups across primary and secondary prevention, nor do they report, in accordance with explicit judgments of assumed patients' values and preferences, absolute benefits and harms and potential treatment burdens. RECOMMENDATIONS: The guideline panel provided mostly weak recommendations, which means we rely on shared decision making when applying these recommendations. For adults already using statins, the panel suggests adding a second lipid-lowering drug in people at very high and high cardiovascular risk but recommends against adding it in people at low cardiovascular risk. For adults who are intolerant to statins, the panel recommends using a lipid-lowering drug in people at very high and high cardiovascular risk but against adding it in those at low cardiovascular risk. When choosing to add another lipid-lowering drug, the panel suggests ezetimibe in preference to PCSK9 inhibitors. The panel suggests further adding a PCSK9 inhibitor to ezetimibe for adults already taking statins at very high risk and those at very high and high risk who are intolerant to statins. HOW THIS GUIDELINE WAS CREATED: An international panel including patients, clinicians, and methodologists produced these recommendations following standards for trustworthy guidelines and using the GRADE approach. The panel identified four risk groups of patients (low, moderate, high, and very high cardiovascular risk) and primarily applied an individual patient perspective in moving from evidence to recommendations, though societal issues were a secondary consideration. The panel considered the balance of benefits and harms and burdens of starting a PCSK9 inhibitor and/or ezetimibe, making assumptions of adults' average values and preferences. Interactive evidence summaries and decision aids accompany multi-layered recommendations, developed in an online authoring and publication platform (www.magicapp.org) that also allows re-use and adaptation. THE EVIDENCE: A linked systematic review and network meta-analysis (14 trials including 83 660 participants) of benefits found that PCSK9 inhibitors or ezetimibe probably reduce myocardial infarctions and stroke in patients with very high and high cardiovascular risk, with no impact on mortality (moderate to high certainty evidence), but not in those with moderate and low cardiovascular risk. PCSK9 inhibitors may have similar effects to ezetimibe on reducing non-fatal myocardial infarction or stroke (low certainty evidence). These relative benefits were consistent, but their absolute magnitude varied based on cardiovascular risk in individual patients (for example, for 1000 people treated with PCSK9 inhibitors in addition to statins over five years, benefits ranged from 2 fewer strokes in the lowest risk to 21 fewer in the highest risk). Two systematic reviews on harms found no important adverse events for these drugs (moderate to high certainty evidence). PCSK9 inhibitors require injections that sometimes result in injection site reactions (best estimate 15 more per 1000 in a 5 year timeframe), representing a burden and harm that may matter to patients. The MATCH-IT decision support tool allows you to interact with the evidence and your patients across the alternative options: https://magicevidence.org/match-it/220504dist-lipid-lowering-drugs/. UNDERSTANDING THE RECOMMENDATIONS: The stratification into four cardiovascular risk groups means that, to use the recommendations, physicians need to identify their patient's risk first. We therefore suggest, specific to various geographical regions, using some reliable risk calculators that estimate patients' cardiovascular risk based on a mix of known risk factors. The largely weak recommendations concerning the addition of ezetimibe or PCSK9 inhibitors reflect what the panel considered to be a close balance between small reductions in stroke and myocardial infarctions weighed against the burdens and limited harms.Because of the anticipated large variability of patients' values and preferences, well informed choices warrant shared decision making. Interactive evidence summaries and decision aids linked to the recommendations can facilitate such shared decisions. The strong recommendations against adding another drug in people at low cardiovascular risk reflect what the panel considered to be a burden without important benefits. The strong recommendation for adding either ezetimibe or PCSK9 inhibitors in people at high and very high cardiovascular risk reflect a clear benefit.The panel recognised the key uncertainty in the evidence concerning patient values and preferences, namely that what most people consider important reductions in cardiovascular risks, weighed against burdens and harms, remains unclear. Finally, availability and costs will influence decisions when healthcare systems, clinicians, or people consider adding ezetimibe or PCSK9 inhibitors.
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Anticolesterolemiantes , Enfermedades Cardiovasculares , Inhibidores de Hidroximetilglutaril-CoA Reductasas , Infarto del Miocardio , Accidente Cerebrovascular , Adulto , Anticolesterolemiantes/efectos adversos , Enfermedades Cardiovasculares/inducido químicamente , LDL-Colesterol , Ezetimiba/uso terapéutico , Humanos , Inhibidores de Hidroximetilglutaril-CoA Reductasas/uso terapéutico , Infarto del Miocardio/tratamiento farmacológico , Inhibidores de PCSK9 , Proproteína Convertasa 9 , Accidente Cerebrovascular/tratamiento farmacológicoRESUMEN
BACKGROUND: The management of anticoagulation therapy around the time of catheter ablation (CA) procedure for adults with arrhythmia is critical and yet is variable in clinical practice. The ideal approach for safe and effective perioperative management should balance the risk of bleeding during uninterrupted anticoagulation while minimising the risk of thromboembolic events with interrupted therapy. OBJECTIVES: To compare the efficacy and harms of interrupted versus uninterrupted anticoagulation therapy for catheter ablation (CA) in adults with arrhythmias. SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase, and SCI-Expanded on the Web of Science for randomised controlled trials on 5 January 2021. We also searched three registers on 29 May 2021 to identify ongoing or unpublished trials. We performed backward and forward searches on reference lists of included trials and other systematic reviews and contacted experts in the field. We applied no restrictions on language or publication status. SELECTION CRITERIA: We included randomised controlled trials comparing uninterrupted anticoagulation with any modality of interruption with or without heparin bridging for CA in adults aged 18 years or older with arrhythmia. DATA COLLECTION AND ANALYSIS: Two review authors conducted independent screening, data extraction, and assessment of risk of bias. A third review author resolved disagreements. We extracted data on study population, interruption strategy, ablation procedure, thromboembolic events (stroke or systemic embolism), major and minor bleeding, asymptomatic thromboembolic events, cardiovascular and all-cause mortality, quality of life (QoL), length of hospital stay, cost, and source of funding. We used GRADE to assess the certainty of the evidence. MAIN RESULTS: We identified 12 studies (4714 participants) that compared uninterrupted periprocedural anticoagulation with interrupted anticoagulation. Studies performed an interruption strategy by either a complete interruption (one study) or by a minimal interruption (11 studies), of which a single-dose skipped strategy was used (nine studies) or two-dose skipped strategy (two studies), with or without heparin bridging. Studies included participants with a mean age of 65 years or greater, with only two studies conducted in relatively younger individuals (mean age less than 60 years). Paroxysmal atrial fibrillation (AF) was the primary type of AF in all studies, and seven studies included other types of AF (persistent and long-standing persistent). Most participants had CHADS2 or CHADS2-VASc demonstrating a low-moderate risk of stroke, with almost all participants having normal or mildly reduced renal function. Ablation source using radiofrequency energy was the most common (seven studies). Ten studies (2835 participants) were conducted in East Asian countries (Japan, China, and South Korea), while the remaining two studies were conducted in the USA. Eight studies were conducted in a single centre. Postablation follow-up was variable among studies at less than 30 days (three studies), 30 days (six studies), and more than 30 days postablation (three studies). Overall, the meta-analysis showed high uncertainty of the effect between the interrupted strategy compared to uninterrupted strategy on the primary outcomes of thromboembolic events (risk ratio (RR) 1.76, 95% confidence interval (CI) 0.33 to 9.46; I2 = 59%; 6 studies, 3468 participants; very low-certainty evidence). However, subgroup analysis showed that uninterrupted vitamin A antagonist (VKA) is associated with a lower risk of thromboembolic events without increasing the risk of bleeding. There is also uncertainty on the outcome of major bleeding events (RR 1.10, 95% CI 0.59 to 2.05; I2 = 6%; 10 studies, 4584 participants; low-certainty evidence). The uncertainty was also evident for the secondary outcomes of minor bleeding (RR 1.01, 95% CI 0.46 to 2.22; I2 = 87%; 9 studies, 3843 participants; very low-certainty evidence), all-cause mortality (RR 0.34, 95% CI 0.01 to 8.21; 442 participants; low-certainty evidence) and asymptomatic thromboembolic events (RR 1.45, 95% CI 0.85 to 2.47; I2 = 56%; 6 studies, 1268 participants; very low-certainty evidence). There was a lower risk of the composite endpoint of thromboembolic events (stroke, systemic embolism, major bleeding, and all-cause mortality) in the interrupted compared to uninterrupted arm (RR 0.23, 95% CI 0.07 to 0.81; 1 study, 442 participants; low-certainty evidence). In general, the low event rates, different comparator anticoagulants, and use of different ablation procedures may be the cause of imprecision and heterogeneity observed. AUTHORS' CONCLUSIONS: This meta-analysis showed that the evidence is uncertain to inform the decision to either interrupt or continue anticoagulation therapy around CA procedure in adults with arrhythmia on outcomes of thromboembolic events, major and minor bleeding, all-cause mortality, asymptomatic thromboembolic events, and a composite endpoint of thromboembolic events (stroke, systemic embolism, major bleeding, and all-cause mortality). Most studies in the review adopted a minimal interruption strategy which has the advantage of reducing the risk of bleeding while maintaining a lower level of anticoagulation to prevent periprocedural thromboembolism, hence low event rates on the primary outcomes of thromboembolism and bleeding. The one study that adopted a complete interruption of VKA showed that uninterrupted VKA reduces the risk of thromboembolism without increasing the risk of bleeding. Hence, future trials with larger samples, tailored to a more generalisable population and using homogeneous periprocedural anticoagulant therapy and ablation source are required to address the safety and efficacy of the optimal management of anticoagulant therapy prior to ablation.
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Ablación por Catéter , Calidad de Vida , Adulto , Anciano , Anticoagulantes/efectos adversos , Arritmias Cardíacas , Heparina/efectos adversos , Humanos , Persona de Mediana EdadRESUMEN
BACKGROUND: Viral epidemics or pandemics of acute respiratory infections (ARIs) pose a global threat. Examples are influenza (H1N1) caused by the H1N1pdm09 virus in 2009, severe acute respiratory syndrome (SARS) in 2003, and coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 in 2019. Antiviral drugs and vaccines may be insufficient to prevent their spread. This is an update of a Cochrane Review published in 2007, 2009, 2010, and 2011. The evidence summarised in this review does not include results from studies from the current COVID-19 pandemic. OBJECTIVES: To assess the effectiveness of physical interventions to interrupt or reduce the spread of acute respiratory viruses. SEARCH METHODS: We searched CENTRAL, PubMed, Embase, CINAHL on 1 April 2020. We searched ClinicalTrials.gov, and the WHO ICTRP on 16 March 2020. We conducted a backwards and forwards citation analysis on the newly included studies. SELECTION CRITERIA: We included randomised controlled trials (RCTs) and cluster-RCTs of trials investigating physical interventions (screening at entry ports, isolation, quarantine, physical distancing, personal protection, hand hygiene, face masks, and gargling) to prevent respiratory virus transmission. In previous versions of this review we also included observational studies. However, for this update, there were sufficient RCTs to address our study aims. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. We used GRADE to assess the certainty of the evidence. Three pairs of review authors independently extracted data using a standard template applied in previous versions of this review, but which was revised to reflect our focus on RCTs and cluster-RCTs for this update. We did not contact trialists for missing data due to the urgency in completing the review. We extracted data on adverse events (harms) associated with the interventions. MAIN RESULTS: We included 44 new RCTs and cluster-RCTs in this update, bringing the total number of randomised trials to 67. There were no included studies conducted during the COVID-19 pandemic. Six ongoing studies were identified, of which three evaluating masks are being conducted concurrent with the COVID pandemic, and one is completed. Many studies were conducted during non-epidemic influenza periods, but several studies were conducted during the global H1N1 influenza pandemic in 2009, and others in epidemic influenza seasons up to 2016. Thus, studies were conducted in the context of lower respiratory viral circulation and transmission compared to COVID-19. The included studies were conducted in heterogeneous settings, ranging from suburban schools to hospital wards in high-income countries; crowded inner city settings in low-income countries; and an immigrant neighbourhood in a high-income country. Compliance with interventions was low in many studies. The risk of bias for the RCTs and cluster-RCTs was mostly high or unclear. Medical/surgical masks compared to no masks We included nine trials (of which eight were cluster-RCTs) comparing medical/surgical masks versus no masks to prevent the spread of viral respiratory illness (two trials with healthcare workers and seven in the community). There is low certainty evidence from nine trials (3507 participants) that wearing a mask may make little or no difference to the outcome of influenza-like illness (ILI) compared to not wearing a mask (risk ratio (RR) 0.99, 95% confidence interval (CI) 0.82 to 1.18. There is moderate certainty evidence that wearing a mask probably makes little or no difference to the outcome of laboratory-confirmed influenza compared to not wearing a mask (RR 0.91, 95% CI 0.66 to 1.26; 6 trials; 3005 participants). Harms were rarely measured and poorly reported. Two studies during COVID-19 plan to recruit a total of 72,000 people. One evaluates medical/surgical masks (N = 6000) (published Annals of Internal Medicine, 18 Nov 2020), and one evaluates cloth masks (N = 66,000). N95/P2 respirators compared to medical/surgical masks We pooled trials comparing N95/P2 respirators with medical/surgical masks (four in healthcare settings and one in a household setting). There is uncertainty over the effects of N95/P2 respirators when compared with medical/surgical masks on the outcomes of clinical respiratory illness (RR 0.70, 95% CI 0.45 to 1.10; very low-certainty evidence; 3 trials; 7779 participants) and ILI (RR 0.82, 95% CI 0.66 to 1.03; low-certainty evidence; 5 trials; 8407 participants). The evidence is limited by imprecision and heterogeneity for these subjective outcomes. The use of a N95/P2 respirator compared to a medical/surgical mask probably makes little or no difference for the objective and more precise outcome of laboratory-confirmed influenza infection (RR 1.10, 95% CI 0.90 to 1.34; moderate-certainty evidence; 5 trials; 8407 participants). Restricting the pooling to healthcare workers made no difference to the overall findings. Harms were poorly measured and reported, but discomfort wearing medical/surgical masks or N95/P2 respirators was mentioned in several studies. One ongoing study recruiting 576 people compares N95/P2 respirators with medical surgical masks for healthcare workers during COVID-19. Hand hygiene compared to control Settings included schools, childcare centres, homes, and offices. In a comparison of hand hygiene interventions with control (no intervention), there was a 16% relative reduction in the number of people with ARIs in the hand hygiene group (RR 0.84, 95% CI 0.82 to 0.86; 7 trials; 44,129 participants; moderate-certainty evidence), suggesting a probable benefit. When considering the more strictly defined outcomes of ILI and laboratory-confirmed influenza, the estimates of effect for ILI (RR 0.98, 95% CI 0.85 to 1.13; 10 trials; 32,641 participants; low-certainty evidence) and laboratory-confirmed influenza (RR 0.91, 95% CI 0.63 to 1.30; 8 trials; 8332 participants; low-certainty evidence) suggest the intervention made little or no difference. We pooled all 16 trials (61,372 participants) for the composite outcome of ARI or ILI or influenza, with each study only contributing once and the most comprehensive outcome reported. The pooled data showed that hand hygiene may offer a benefit with an 11% relative reduction of respiratory illness (RR 0.89, 95% CI 0.84 to 0.95; low-certainty evidence), but with high heterogeneity. Few trials measured and reported harms. There are two ongoing studies of handwashing interventions in 395 children outside of COVID-19. We identified one RCT on quarantine/physical distancing. Company employees in Japan were asked to stay at home if household members had ILI symptoms. Overall fewer people in the intervention group contracted influenza compared with workers in the control group (2.75% versus 3.18%; hazard ratio 0.80, 95% CI 0.66 to 0.97). However, those who stayed at home with their infected family members were 2.17 times more likely to be infected. We found no RCTs on eye protection, gowns and gloves, or screening at entry ports. AUTHORS' CONCLUSIONS: The high risk of bias in the trials, variation in outcome measurement, and relatively low compliance with the interventions during the studies hamper drawing firm conclusions and generalising the findings to the current COVID-19 pandemic. There is uncertainty about the effects of face masks. The low-moderate certainty of the evidence means our confidence in the effect estimate is limited, and that the true effect may be different from the observed estimate of the effect. The pooled results of randomised trials did not show a clear reduction in respiratory viral infection with the use of medical/surgical masks during seasonal influenza. There were no clear differences between the use of medical/surgical masks compared with N95/P2 respirators in healthcare workers when used in routine care to reduce respiratory viral infection. Hand hygiene is likely to modestly reduce the burden of respiratory illness. Harms associated with physical interventions were under-investigated. There is a need for large, well-designed RCTs addressing the effectiveness of many of these interventions in multiple settings and populations, especially in those most at risk of ARIs.
Asunto(s)
Higiene de las Manos , Máscaras , Infecciones del Sistema Respiratorio/prevención & control , Virosis/prevención & control , Esparcimiento de Virus , Sesgo , COVID-19/epidemiología , COVID-19/prevención & control , Estudios de Casos y Controles , Epidemias , Humanos , Subtipo H1N1 del Virus de la Influenza A , Gripe Humana/epidemiología , Gripe Humana/transmisión , Gripe Humana/virología , Ensayos Clínicos Controlados Aleatorios como Asunto/estadística & datos numéricos , Infecciones del Sistema Respiratorio/epidemiología , Infecciones del Sistema Respiratorio/transmisión , Infecciones del Sistema Respiratorio/virología , SARS-CoV-2 , Síndrome Respiratorio Agudo Grave/epidemiología , Síndrome Respiratorio Agudo Grave/prevención & control , Virosis/epidemiología , Virosis/transmisiónRESUMEN
RATIONALE, AIMS, AND OBJECTIVES: Clinical practice guidelines (CPGs) are significant tools for evidence-based health care quality improvement. The CPG program at King Saud University was launched as a quality improvement program to fulfil the international accreditation standards. This program was a collaboration between the Research Chair for Evidence-Based Healthcare and Knowledge Translation and the Quality Management Department. This study aims to develop a fast-track method for adaptation of evidence-based CPGs and describe results of the program. METHODS: Twenty-two clinical departments participated in the program. Following a CPGs awareness week directed to all health care professionals (HCPs), 22 teams were trained to set priorities, search, screen, assess, select, and customize the best available CPGs. The teams were technically supported by the program's CPG advisors. To address the local health care context, a modified version of the ADAPTE was used where recommendations were either accepted or rejected but not changed. A strict peer-review process for clinical content and methodology was employed. RESULTS: In addition to raising awareness and building capacity, 35 CPGs were approved for implementation by March 2018. These CPGs were integrated with other existing projects such as accreditation, electronic medical records, performance management, and training and education. Preliminary implementation audits suggest a positive impact on patient outcomes. Leadership commitment was a strength, but the high turnover of the team members required frequent and extensive training for HCPs. CONCLUSION: This model for CPG adaptation represents a quick, practical, economical method with a sense of ownership by staff. Using this modified version can be replicated in other countries to assess its validity.
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Vías Clínicas/normas , Práctica Clínica Basada en la Evidencia/métodos , Mejoramiento de la Calidad/organización & administración , Creación de Capacidad/métodos , Creación de Capacidad/organización & administración , Hospitales Universitarios , Humanos , Guías de Práctica Clínica como Asunto , Arabia Saudita , Desarrollo SostenibleRESUMEN
RATIONALE, AIMS, AND OBJECTIVES: Implementation of clinical practice guidelines (CPGs) has been shown to reduce variation in practice and improve health care quality and patients' safety. There is a limited experience of CPG implementation (CPGI) in the Middle East. The CPG program in our institution was launched in 2009. The Quality Management department conducted a Failure Mode and Effect Analysis (FMEA) for further improvement of CPGI. METHODS: This is a prospective study of a qualitative/quantitative design. Our FMEA included (1) process review and recording of the steps and activities of CPGI; (2) hazard analysis by recording activity-related failure modes and their effects, identification of actions required, assigned severity, occurrence, and detection scores for each failure mode and calculated the risk priority number (RPN) by using an online interactive FMEA tool; (3) planning: RPNs were prioritized, recommendations, and further planning for new interventions were identified; and (4) monitoring: after reduction or elimination of the failure mode. The calculated RPN will be compared with subsequent analysis in post-implementation phase. RESULTS: The data were scrutinized from a feedback of quality team members using a FMEA framework to enhance the implementation of 29 adapted CPGs. The identified potential common failure modes with the highest RPN (≥ 80) included awareness/training activities, accessibility of CPGs, fewer advocates from clinical champions, and CPGs auditing. Actions included (1) organizing regular awareness activities, (2) making CPGs printed and electronic copies accessible, (3) encouraging senior practitioners to get involved in CPGI, and (4) enhancing CPGs auditing as part of the quality sustainability plan. CONCLUSION: In our experience, FMEA could be a useful tool to enhance CPGI. It helped us to identify potential barriers and prepare relevant solutions.
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Adhesión a Directriz/normas , Análisis de Modo y Efecto de Fallas en la Atención de la Salud/métodos , Pautas de la Práctica en Medicina/normas , Gestión de Riesgos/organización & administración , Humanos , Guías de Práctica Clínica como Asunto , Estudios Prospectivos , Mejoramiento de la Calidad , Arabia SauditaRESUMEN
Importance: No guidelines exist currently for guideline panels and others considering changes to disease definitions. Panels frequently widen disease definitions, increasing the proportion of the population labeled as unwell and potentially causing harm to patients. We set out to develop a checklist of issues, with guidance, for panels to consider prior to modifying a disease definition. Observations: We assembled a multidisciplinary, multicontinent working group of 13 members, including members from the Guidelines International Network, Grading of Recommendations Assessment, Development and Evaluation working group, and the World Health Organisation. We used a 5-step process to develop the checklist: (1) a literature review of issues, (2) a draft outline document, (3) a Delphi process of feedback on the list of issues, (4) a 1-day face-to-face meeting, and (5) further refinement of the checklist. The literature review identified 12 potential issues. From these, the group developed an 8-item checklist that consisted of definition changes, number of people affected, trigger, prognostic ability, disease definition precision and accuracy, potential benefits, potential harms, and the balance between potential harms and benefits. The checklist is accompanied by an explanation of each item and the types of evidence to assess each one. We used a panel's recent consideration of a proposed change in the definition of gestational diabetes mellitus (GDM) to illustrate use of the checklist. Conclusions and Relevance: We propose that the checklist be piloted and validated by groups developing new guidelines. We anticipate that the use of the checklist will be a first step to guidance and better documentation of definition changes prior to introducing modified disease definitions.
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Lista de Verificación , Enfermedad , Guías como Asunto , Terminología como Asunto , Medicina Clínica/métodos , Current Procedural Terminology , Manejo de la Enfermedad , HumanosRESUMEN
Conflicts of interest (COIs) have been defined by the American Thoracic Society as "a divergence between an individual's private interests and his or her professional obligations such that an independent observer might reasonably question whether the individual's professional actions or decisions are motivated by personal gain, such as direct financial, academic advancement, clinical revenue streams, or community standing." In the context of guideline development, the concerns are not simply about identifying and disclosing direct financial or indirect COIs. Despite this recognition, the management of COIs in guidelines is often unsatisfactory. In response to requests from its international membership and informed by existing syntheses of the evidence and policies of international organizations, the Guidelines International Network Board of Trustees developed guidance on the disclosure of interests and management of COIs. Current approaches are relatively similar throughout the guideline development community, with an increasing recognition of the importance of disclosing and managing indirect COIs. Although there are differences in detail among the approaches, the similarities allow for the formulation of 9 core principles for managing COIs. In formulating these principles, the Guidelines International Network Board of Trustees recognizes that COIs cannot be totally avoided when panel members are being chosen for certain guidelines or in certain settings; thus, the important issue is the management of COIs in a fair, judicious, transparent manner.
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Investigación Biomédica/ética , Conflicto de Intereses , Revelación , Guías como Asunto , HumanosRESUMEN
Translation of research evidence into public health programs is lagging in Eastern Mediterranean Region. Graduate level public health curriculum at King Saud University (KSU), College of Medicine, Riyadh, is designed to equip students to integrate best available evidence in public health decision making. The objectives of study were to explore students' opinion about the evidence based public health (EBPH) courses and to survey the knowledge, opinion, and attitude of the students towards EBPH and perceived barriers for implementation of EBPH in decision making in public health. EBPH courses are designed based on a sequential framework. A survey was conducted at the completion of EBPH courses. Forty-five graduate students were invited to complete a validated self-administered questionnaire. It included questions about demography, opinion, and attitude towards EBPH and perceived barriers towards implementation of EBPH in the work environment. The response rate was 73%. Mean age of students was 30.1 (SD 2.3) years, and 51% were males. More than 80% had sound knowledge and could appreciate the importance of EBPH. The main perceived barriers to incorporate EBPH in decision making were lack of system of communication between researchers and policy makers and scarcity of research publications related to the public health problems.
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Toma de Decisiones , Práctica Clínica Basada en la Evidencia , Estudiantes de Salud Pública , Adulto , Actitud , Femenino , Humanos , Masculino , Encuestas y Cuestionarios , UniversidadesRESUMEN
BACKGROUND: Different types of influenza vaccines are currently produced worldwide. Vaccination of pregnant women is recommended internationally, while healthy adults are targeted in North America. OBJECTIVES: To identify, retrieve and assess all studies evaluating the effects (efficacy, effectiveness and harm) of vaccines against influenza in healthy adults, including pregnant women. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2013, Issue 2), MEDLINE (January 1966 to May 2013) and EMBASE (1990 to May 2013). SELECTION CRITERIA: Randomised controlled trials (RCTs) or quasi-RCTs comparing influenza vaccines with placebo or no intervention in naturally occurring influenza in healthy individuals aged 16 to 65 years. We also included comparative studies assessing serious and rare harms. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed trial quality and extracted data. MAIN RESULTS: We included 90 reports containing 116 data sets; among these 69 were clinical trials of over 70,000 people, 27 were comparative cohort studies (about eight million people) and 20 were case-control studies (nearly 25,000 people). We retrieved 23 reports of the effectiveness and safety of vaccine administration in pregnant women (about 1.6 million mother-child couples).The overall effectiveness of parenteral inactivated vaccine against influenza-like illness (ILI) is limited, corresponding to a number needed to vaccinate (NNV) of 40 (95% confidence interval (CI) 26 to 128). The overall efficacy of inactivated vaccines in preventing confirmed influenza has a NNV of 71 (95% CI 64 to 80). The difference between these two values depends on the different incidence of ILI and confirmed influenza among the study populations: 15.6% of unvaccinated participants versus 9.9% of vaccinated participants developed ILI symptoms, whilst only 2.4% and 1.1%, respectively, developed laboratory-confirmed influenza.No RCTs assessing vaccination in pregnant women were found. The only evidence available comes from observational studies with modest methodological quality. On this basis, vaccination shows very limited effects: NNV 92 (95% CI 63 to 201) against ILI in pregnant women and NNV 27 (95% CI 18 to 185) against laboratory-confirmed influenza in newborns from vaccinated women.Live aerosol vaccines have an overall effectiveness corresponding to a NNV 46 (95% CI 29 to 115).The performance of one-dose or two-dose whole virion pandemic vaccines was higher, showing a NNV of 16 (95% CI 14 to 20) against ILI and a NNV of 35 (95% CI 33 to 47) against influenza, while a limited impact on hospitalisation was found (NNV 94, 95% CI 70 to 1022).Vaccination had a modest effect on time off work and had no effect on hospital admissions or complication rates. Inactivated vaccines caused local harms. No evidence of association with serious adverse events was found, but the harms evidence base was limited.The overall risk of bias in the included trials is unclear because it was not possible to assess the real impact of bias. AUTHORS' CONCLUSIONS: Influenza vaccines have a very modest effect in reducing influenza symptoms and working days lost in the general population, including pregnant women. No evidence of association between influenza vaccination and serious adverse events was found in the comparative studies considered in the review. This review includes 90 studies, 24 of which (26.7%) were funded totally or partially by industry. Out of the 48 RCTs, 17 were industry-funded (35.4%).
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Virus de la Influenza A , Virus de la Influenza B , Adulto , Industria Farmacéutica , Humanos , Gripe Humana/prevención & control , Gripe Humana/virología , Sesgo de Publicación , Apoyo a la Investigación como AsuntoRESUMEN
BACKGROUND: Despite the availability of clinical practice guidelines (CPGs), optimal hypertension control is not achieved in many parts of the world; one of the challenges is the volume of guidelines on this topic and their variable quality. To systematically review the quality, methodology, and consistency of recommendations of recently-developed national CPGs on the diagnosis, assessment and the management of hypertension. METHODOLOGY/PRINCIPAL FINDINGS: MEDLINE, EMBASE, guidelines' websites and Google were searched for CPGs written in English on the general management of hypertension in any clinical setting published between January 2006 and September 2011. Four raters independently appraised each CPG using the AGREE-II instrument and 2 reviewers independently extracted the data. Conflicts were resolved by discussion or the involvement of an additional reviewer. Eleven CPGs were identified. The overall quality ranged from 2.5 to 6 out of 7 on the AGREE-II tool. The highest scores were for "clarity of presentation" (44.4%-88.9%) and the lowest were for "rigour of development" (8.3%-30% for 9 CGPs). None of them clearly reported being newly developed or adapted. Only one reported having a patient representative in its development team. Systematic reviews were not consistently used and only 2 up-to-date Cochrane reviews were cited. Two CPGs graded some recommendations and related that to levels (but not quality) of evidence. The CPGs' recommendations on assessment and non-pharmacological management were fairly consistent. Guidelines varied in the selection of first-line treatment, adjustment of therapy and drug combinations. Important specific aspects of care (e.g. resistant hypertension) were ignored by 6/11 CPGs. The CPGs varied in methodological quality, suggesting that their implementation might not result in less variation of care or in better health-related outcomes. CONCLUSIONS/SIGNIFICANCE: More efforts are needed to promote the realistic approach of localization or local adaptation of existing high-quality CPGs to the national context.
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Hipertensión/diagnóstico , Hipertensión/terapia , Guías de Práctica Clínica como Asunto , Enfermedades Cardiovasculares/complicaciones , Adhesión a Directriz/estadística & datos numéricos , Humanos , Hipertensión/complicaciones , Guías de Práctica Clínica como Asunto/normas , RiesgoRESUMEN
BACKGROUND: In some current healthcare settings, there is a noticeable absence of national institutions committed to the synthesis and use of evidence in healthcare decision- and policy-making. This absence creates a need to broaden the responsibilities of healthcare providers to include knowledge brokering and advocacy in order to optimize knowledge translation to other stakeholders, especially policy-makers. However, this process requires practitioners and researchers to acquire certain types of knowledge and skills. This article introduces two innovative methods for capacity building in knowledge translation (KT). METHODS: During a workshop aimed at preparing 21 trainers in evidence-based medicine, two innovative methods were used: (1) debate and (2) a knowledge translation project (KTP). The main objective of the debates approach was to strengthen participants' critical thinking abilities by requiring them to search for and appraise evidence and defend their arguments. The KTP was used to introduce participants to the essential steps of knowledge translation and to suggest an extended role for healthcare practitioners, i.e., using evidence to manage not only individual patients but also to a community of patients. Participants' performances were assessed according to a pre-designed scheme. At the end of the workshop, participants' opinions and experiences with the innovative teaching methods were evaluated based on their answers to a questionnaire and the results of small-group discussions. RESULTS: The participants performed well in both the debate and KTP methods. During post-workshop group discussions, they indicated that the debate approach had added a new dimension to their evidence-based medicine skills by adding purpose and motivation. However, they felt that their performances would have been better if they had been offered practical demonstrations of how to conduct the debate. The participants indicated that the KTP enhanced their understanding of the relationships between evidence and implementation, and motivated them to investigate public health problems in addition to individual patient problems. However, some participants maintained that these issues fell outside the scope of their role as doctors. CONCLUSION: Debates and evidence implementation through KTP are generally well accepted by healthcare practitioners as methods by which they can improve their skills in KT.
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Creación de Capacidad/métodos , Medicina Basada en la Evidencia/educación , Medicina Familiar y Comunitaria/educación , Conocimientos, Actitudes y Práctica en Salud , Adulto , Creación de Capacidad/normas , Medicina Familiar y Comunitaria/normas , Femenino , Humanos , Masculino , Persona de Mediana Edad , Formulación de Políticas , Arabia Saudita , Enseñanza/métodosRESUMEN
BACKGROUND AND OBJECTIVES: A new test (Dr. KSU H1N1 RT-PCR kit) was recently developed to provide a less expensive alternative to real-time reverse transcriptase-polymerase chain reaction (RT-PCR). We report the findings of a validation study designed to assess the diagnostic accuracy, including sensitivity and specificity, of the new kit, as compared to real-time RT-PCR. DESIGN AND SETTING: Cross-sectional validation study conducted from 18-22 November 2009 at a primary care clinic for H1N1 at a tertiary care teaching hospital in Riyadh. PATIENTS AND METHODS: Nasopharyngeal swab samples and data on socio-demographic characteristics and symptoms were collected from 186 patients. Swab samples were sent to the laboratory for testing with both real-time RT-PCR and the new Dr. KSU H1N1 RT-PCR kit. We measured the sensitivity and specificity of the new test across the entire sample size and investigated how these values were affected by patient socio-demographic characteristics and symptoms. RESULTS: The outcomes of the two tests were highly correlated (kappa=0.85; P<.0001). The sensitivity and specificity of the new test were 99.11% and 83.78%, respectively. The sensitivity of the new test was affected only minimally (96%-100%) by patient characteristics and number of symptoms. On the other hand, the specificity of the new test varied depending on how soon patients were tested after onset of symptoms (100% specificity when swabs were taken on the first day of the symptoms, decreasing to 75% when swabs were taken on or after the third day). The specificity of the new test also increased with increasing body temperature. CONCLUSION: The new test seems to provide a cost-effective alternative to real-time RT-PCR for diagnosing H1N1 influenza. However, further testing may be needed to verify the efficacy of the test in different settings and communities.
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Subtipo H1N1 del Virus de la Influenza A/aislamiento & purificación , Gripe Humana/diagnóstico , Reacción en Cadena en Tiempo Real de la Polimerasa , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Adolescente , Adulto , Temperatura Corporal , Niño , Preescolar , Análisis Costo-Beneficio , Estudios Transversales , Femenino , Hospitales de Enseñanza , Humanos , Lactante , Gripe Humana/virología , Masculino , Persona de Mediana Edad , Atención Primaria de Salud , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/economía , Arabia Saudita , Sensibilidad y Especificidad , Factores de Tiempo , Adulto JovenRESUMEN
BACKGROUND: Viral epidemics or pandemics of acute respiratory infections like influenza or severe acute respiratory syndrome pose a global threat. Antiviral drugs and vaccinations may be insufficient to prevent their spread. OBJECTIVES: To review the effectiveness of physical interventions to interrupt or reduce the spread of respiratory viruses. SEARCH STRATEGY: We searched The Cochrane Library, the Cochrane Central Register of Controlled Trials (CENTRAL 2010, Issue 3), which includes the Acute Respiratory Infections Group's Specialised Register, MEDLINE (1966 to October 2010), OLDMEDLINE (1950 to 1965), EMBASE (1990 to October 2010), CINAHL (1982 to October 2010), LILACS (2008 to October 2010), Indian MEDLARS (2008 to October 2010) and IMSEAR (2008 to October 2010). SELECTION CRITERIA: In this update, two review authors independently applied the inclusion criteria to all identified and retrieved articles and extracted data. We scanned 3775 titles, excluded 3560 and retrieved full papers of 215 studies, to include 66 papers of 67 studies. We included physical interventions (screening at entry ports, isolation, quarantine, social distancing, barriers, personal protection, hand hygiene) to prevent respiratory virus transmission. We included randomised controlled trials (RCTs), cohorts, case-controls, before-after and time series studies. DATA COLLECTION AND ANALYSIS: We used a standardised form to assess trial eligibility. We assessed RCTs by randomisation method, allocation generation, concealment, blinding and follow up. We assessed non-RCTs for potential confounders and classified them as low, medium and high risk of bias. MAIN RESULTS: We included 67 studies including randomised controlled trials and observational studies with a mixed risk of bias. A total number of participants is not included as the total would be made up of a heterogenous set of observations (participant people, observations on participants and countries (object of some studies)). The risk of bias for five RCTs and most cluster-RCTs was high. Observational studies were of mixed quality. Only case-control data were sufficiently homogeneous to allow meta-analysis. The highest quality cluster-RCTs suggest respiratory virus spread can be prevented by hygienic measures, such as handwashing, especially around younger children. Benefit from reduced transmission from children to household members is broadly supported also in other study designs where the potential for confounding is greater. Nine case-control studies suggested implementing transmission barriers, isolation and hygienic measures are effective at containing respiratory virus epidemics. Surgical masks or N95 respirators were the most consistent and comprehensive supportive measures. N95 respirators were non-inferior to simple surgical masks but more expensive, uncomfortable and irritating to skin. Adding virucidals or antiseptics to normal handwashing to decrease respiratory disease transmission remains uncertain. Global measures, such as screening at entry ports, led to a non-significant marginal delay in spread. There was limited evidence that social distancing was effective, especially if related to the risk of exposure. AUTHORS' CONCLUSIONS: Simple and low-cost interventions would be useful for reducing transmission of epidemic respiratory viruses. Routine long-term implementation of some measures assessed might be difficult without the threat of an epidemic.
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Infecciones del Sistema Respiratorio/prevención & control , Virosis/prevención & control , Esparcimiento de Virus , Estudios de Casos y Controles , Humanos , Gripe Humana/transmisión , Gripe Humana/virología , Ensayos Clínicos Controlados Aleatorios como Asunto , Infecciones del Sistema Respiratorio/transmisión , Infecciones del Sistema Respiratorio/virología , Virosis/transmisiónRESUMEN
BACKGROUND: The measurement of hemoglobin A(1c) (Hb A(1c)) is employed in monitoring of patients with diabetes. Use of point-of-care testing (POCT) for Hb A(1c) results at the time of the patient consultation potentially provides an opportunity for greater interaction between patient and caregiver, and more effective care. OBJECTIVE: To perform a systematic review of current trials to determine whether POCT for Hb A(1c), compared with conventional laboratory testing, improves outcomes for patients with diabetes. METHODS: Searches were undertaken on 4 electronic databases and bibliographies from, and hand searches of, relevant journal papers. Only randomized controlled trials were included. The primary outcome measures were change in Hb A(1c) and treatment intensification. Metaanalyses were performed on the data obtained. RESULTS: Seven trials were found. There was a nonsignificant reduction of 0.09% (95% CI -0.21 to 0.02) in the Hb A(1c) in the POCT compared to the standard group. Although data were collected on the change in proportion of patients reaching a target Hb A(1c) of <7.0%, treatment intensification and heterogeneity in the populations studied and how measures were reported precluded pooling of data and metaanalysis. Positive patient satisfaction was also reported in the studies, as well as limited assessments of costs. CONCLUSIONS: There is an absence of evidence in clinical trial data to date for the effectiveness of POCT for Hb A(1c) in the management of diabetes. In future studies attention to trial design is needed to ensure appropriate selection and stratification of patients, collection of outcome measures, and action taken upon Hb A(1c) results when produced.
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Diabetes Mellitus/terapia , Hemoglobina Glucada/análisis , Sistemas de Atención de Punto , Glucemia/análisis , Diabetes Mellitus/sangre , Humanos , Satisfacción del PacienteRESUMEN
BACKGROUND: Different types of influenza vaccines are currently produced worldwide. Healthy adults are presently targeted mainly in North America. OBJECTIVES: Identify, retrieve and assess all studies evaluating the effects of vaccines against influenza in healthy adults. SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2010, issue 2), MEDLINE (January 1966 to June 2010) and EMBASE (1990 to June 2010). SELECTION CRITERIA: Randomised controlled trials (RCTs) or quasi-RCTs comparing influenza vaccines with placebo or no intervention in naturally-occurring influenza in healthy individuals aged 16 to 65 years. We also included comparative studies assessing serious and rare harms. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed trial quality and extracted data. MAIN RESULTS: We included 50 reports. Forty (59 sub-studies) were clinical trials of over 70,000 people. Eight were comparative non-RCTs and assessed serious harms. Two were reports of harms which could not be introduced in the data analysis. In the relatively uncommon circumstance of vaccine matching the viral circulating strain and high circulation, 4% of unvaccinated people versus 1% of vaccinated people developed influenza symptoms (risk difference (RD) 3%, 95% confidence interval (CI) 2% to 5%). The corresponding figures for poor vaccine matching were 2% and 1% (RD 1, 95% CI 0% to 3%). These differences were not likely to be due to chance. Vaccination had a modest effect on time off work and had no effect on hospital admissions or complication rates. Inactivated vaccines caused local harms and an estimated 1.6 additional cases of Guillain-Barré Syndrome per million vaccinations. The harms evidence base is limited. AUTHORS' CONCLUSIONS: Influenza vaccines have a modest effect in reducing influenza symptoms and working days lost. There is no evidence that they affect complications, such as pneumonia, or transmission.WARNING: This review includes 15 out of 36 trials funded by industry (four had no funding declaration). An earlier systematic review of 274 influenza vaccine studies published up to 2007 found industry funded studies were published in more prestigious journals and cited more than other studies independently from methodological quality and size. Studies funded from public sources were significantly less likely to report conclusions favorable to the vaccines. The review showed that reliable evidence on influenza vaccines is thin but there is evidence of widespread manipulation of conclusions and spurious notoriety of the studies. The content and conclusions of this review should be interpreted in light of this finding.