Therapeutic use of cannabis and cannabinoids: an evidence mapping and appraisal of systematic reviews.

BACKGROUND: Although cannabis and cannabinoids are widely used with therapeutic purposes, their claimed efficacy is highly controversial. For this reason, medical cannabis use is a broad field of research that is rapidly expanding. Our objectives are to identify, characterize, appraise, and organize the current available evidence surrounding therapeutic use of cannabis and cannabinoids, using evidence maps. METHODS: We searched PubMed, EMBASE, The Cochrane Library and CINAHL, to identify systematic reviews (SRs) published from their inception up to December 2017. Two authors assessed eligibility and extracted data independently. We assessed methodological quality of the included SRs using the AMSTAR tool. To illustrate the extent of use of medical cannabis, we organized the results according to identified PICO questions using bubble plots corresponding to different clinical scenarios. RESULTS: A total of 44 SRs published between 2001 and 2017 were included in this evidence mapping with data from 158 individual studies. We extracted 96 PICO questions in the following medical conditions: multiple sclerosis, movement disorders (e.g. Tourette Syndrome, Parkinson Disease), psychiatry conditions, Alzheimer disease, epilepsy, acute and chronic pain, cancer, neuropathic pain, symptoms related to cancer (e.g. emesis and anorexia related with chemotherapy), rheumatic disorders, HIV-related symptoms, glaucoma, and COPD. The evidence about these conditions is heterogeneous regarding the conclusions and the quality of the individual primary studies. The quality of the SRs was moderate to high according to AMSTAR scores. CONCLUSIONS: Evidence on medical uses of cannabis is broad. However, due to methodological limitations, conclusions were weak in most of the assessed comparisons. Evidence mapping methodology is useful to perform an overview of available research, since it is possible to systematically describe the extent and distribution of evidence, and to organize scattered data.

Interventions for preventing high altitude illness: Part 3. Miscellaneous and non-pharmacological interventions.

BACKGROUND: High altitude illness (HAI) is a term used to describe a group of mainly cerebral and pulmonary syndromes that can occur during travel to elevations above 2500 metres (˜ 8200 feet). Acute mountain sickness (AMS), high altitude cerebral oedema (HACE), and high altitude pulmonary oedema (HAPE) are reported as potential medical problems associated with high altitude ascent. In this, the third of a series of three reviews about preventive strategies for HAI, we assessed the effectiveness of miscellaneous and non-pharmacological interventions. OBJECTIVES: To assess the clinical effectiveness and adverse events of miscellaneous and non-pharmacological interventions for preventing acute HAI in people who are at risk of developing high altitude illness in any setting. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, LILACS and the World Health Organization International Clinical Trials Registry Platform (WHO ICTRP) in January 2019. We adapted the MEDLINE strategy for searching the other databases. We used a combination of thesaurus-based and free-text search terms. We scanned the reference lists and citations of included trials and any relevant systematic reviews that we identified for further references to additional trials. SELECTION CRITERIA: We included randomized controlled trials conducted in any setting where non-pharmacological and miscellaneous interventions were employed to prevent acute HAI, including preacclimatization measures and the administration of non-pharmacological supplements. We included trials involving participants who are at risk of developing high altitude illness (AMS or HACE, or HAPE, or both). We included participants with, and without, a history of high altitude illness. We applied no age or gender restrictions. We included trials where the relevant intervention was administered before the beginning of ascent. DATA COLLECTION AND ANALYSIS: We used the standard methodological procedures employed by Cochrane. MAIN RESULTS: We included 20 studies (1406 participants, 21 references) in this review. Thirty studies (14 ongoing, and 16 pending classification (awaiting)) will be considered in future versions of this suite of three reviews as appropriate. We report the results for the primary outcome of this review (risk of AMS) by each group of assessed interventions.Group 1. Preacclimatization and other measures based on pressureUse of simulated altitude or remote ischaemic preconditioning (RIPC) might not improve the risk of AMS on subsequent exposure to altitude, but this effect is uncertain (simulated altitude: risk ratio (RR) 1.18, 95% confidence interval (CI) 0.82 to 1.71; I² = 0%; 3 trials, 140 participants; low-quality evidence. RIPC: RR 3.0, 95% CI 0.69 to 13.12; 1 trial, 40 participants; low-quality evidence). We found evidence of improvement of this risk using positive end-expiratory pressure (PEEP), but this information was derived from a cross-over trial with a limited number of participants (OR 3.67, 95% CI 1.38 to 9.76; 1 trial, 8 participants; low-quality evidence). We found scarcity of evidence about the risk of adverse events for these interventions.Group 2. Supplements and vitaminsSupplementation of antioxidants, medroxyprogesterone, iron or Rhodiola crenulata might not improve the risk of AMS on exposure to high altitude, but this effect is uncertain (antioxidants: RR 0.58, 95% CI 0.32 to 1.03; 1 trial, 18 participants; low-quality evidence. Medroxyprogesterone: RR 0.71, 95% CI 0.48 to 1.05; I² = 0%; 2 trials, 32 participants; low-quality evidence. Iron: RR 0.65, 95% CI 0.38 to 1.11; I² = 0%; 2 trials, 65 participants; low-quality evidence. R crenulata: RR 1.00, 95% CI 0.78 to 1.29; 1 trial, 125 participants; low-quality evidence). We found evidence of improvement of this risk with the administration of erythropoietin, but this information was extracted from a trial with issues related to risk of bias and imprecision (RR 0.41, 95% CI 0.20 to 0.84; 1 trial, 39 participants; very low-quality evidence). Regarding administration of ginkgo biloba, we did not perform a pooled estimation of RR for AMS due to considerable heterogeneity between the included studies (I² = 65%). RR estimates from the individual studies were conflicting (from 0.05 to 1.03; low-quality evidence). We found scarcity of evidence about the risk of adverse events for these interventions.Group 3. Other comparisonsWe found heterogeneous evidence regarding the risk of AMS when ginkgo biloba was compared with acetazolamide (I² = 63%). RR estimates from the individual studies were conflicting (estimations from 0.11 (95% CI 0.01 to 1.86) to 2.97 (95% CI 1.70 to 5.21); low-quality evidence). We found evidence of improvement when ginkgo biloba was administered along with acetazolamide, but this information was derived from a single trial with issues associated to risk of bias (compared to ginkgo biloba alone: RR 0.43, 95% CI 0.26 to 0.71; 1 trial, 311 participants; low-quality evidence). Administration of medroxyprogesterone plus acetazolamide did not improve the risk of AMS when compared to administration of medroxyprogesterone or acetazolamide alone (RR 1.33, 95% CI 0.50 to 3.55; 1 trial, 12 participants; low-quality evidence). We found scarcity of evidence about the risk of adverse events for these interventions. AUTHORS' CONCLUSIONS: This Cochrane Review is the final in a series of three providing relevant information to clinicians, and other interested parties, on how to prevent high altitude illness. The assessment of non-pharmacological and miscellaneous interventions suggests that there is heterogeneous and even contradictory evidence related to the effectiveness of these prophylactic strategies. Safety of these interventions remains as an unclear issue due to lack of assessment. Overall, the evidence is limited due to its quality (low to very low), the relative paucity of that evidence and the number of studies pending classification for the three reviews belonging to this series (30 studies either awaiting classification or ongoing). Additional studies, especially those comparing with pharmacological alternatives (such as acetazolamide) are required, in order to establish or refute the strategies evaluated in this review.

Interventions for treating acute high altitude illness.

BACKGROUND: Acute high altitude illness is defined as a group of cerebral and pulmonary syndromes that can occur during travel to high altitudes. It is more common above 2500 metres, but can be seen at lower elevations, especially in susceptible people. Acute high altitude illness includes a wide spectrum of syndromes defined under the terms 'acute mountain sickness' (AMS), 'high altitude cerebral oedema' and 'high altitude pulmonary oedema'. There are several interventions available to treat this condition, both pharmacological and non-pharmacological; however, there is a great uncertainty regarding their benefits and harms. OBJECTIVES: To assess the clinical effectiveness, and safety of interventions (non-pharmacological and pharmacological), as monotherapy or in any combination, for treating acute high altitude illness. SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase, LILACS, ISI Web of Science, CINAHL, Wanfang database and the World Health Organization International Clinical Trials Registry Platform for ongoing studies on 10 August 2017. We did not apply any language restriction. SELECTION CRITERIA: We included randomized controlled trials evaluating the effects of pharmacological and non-pharmacological interventions for individuals suffering from acute high altitude illness: acute mountain sickness, high altitude pulmonary oedema or high altitude cerebral oedema. DATA COLLECTION AND ANALYSIS: Two review authors independently assessed the eligibility of study reports, the risk of bias for each and performed the data extraction. We resolved disagreements through discussion with a third author. We assessed the quality of evidence with GRADE. MAIN RESULTS: We included 13 studies enrolling a total of 468 participants. We identified two ongoing studies. All studies included adults, and two studies included both teenagers and adults. The 13 studies took place in high altitude areas, mostly in the European Alps. Twelve studies included participants with acute mountain sickness, and one study included participants with high altitude pulmonary oedema. Follow-up was usually less than one day. We downgraded the quality of the evidence in most cases due to risk of bias and imprecision. We report results for the main comparisons as follows.Non-pharmacological interventions (3 studies, 124 participants)All-cause mortality and complete relief of AMS symptoms were not reported in the three included trials. One study in 64 participants found that a simulated descent of 193 millibars versus 20 millibars may reduce the average of symptoms to 2.5 vs 3.1 units after 12 hours of treatment (clinical score ranged from 0 to 11 ‒ worse; reduction of 0.6 points on average with the intervention; low quality of evidence). In addition, no complications were found with use of hyperbaric chambers versus supplementary oxygen (one study; 29 participants; low-quality evidence).Pharmacological interventions (11 trials, 375 participants)All-cause mortality was not reported in the 11 included trials. One trial found a greater proportion of participants with complete relief of AMS symptoms after 12 and 16 hours when dexamethasone was administered in comparison with placebo (47.1% versus 0%, respectively; one study; 35 participants; low quality of evidence). Likewise, when acetazolamide was compared with placebo, the effects on symptom severity was uncertain (standardized mean difference (SMD) -1.15, 95% CI -2.56 to 0.27; 2 studies, 25 participants; low-quality evidence). One trial of dexamethasone in comparison with placebo in 35 participants found a reduction in symptom severity (difference on change in the AMS score: 3.7 units reported by authors; moderate quality of evidence). The effects from two additional trials comparing gabapentin with placebo and magnesium with placebo on symptom severity at the end of treatment were uncertain. For gabapentin versus placebo: mean visual analogue scale (VAS) score of 2.92 versus 4.75, respectively; 24 participants; low quality of evidence. For magnesium versus placebo: mean scores of 9 and 10.3 units, respectively; 25 participants; low quality of evidence). The trials did not find adverse events from either treatment (low quality of evidence). One trial comparing magnesium sulphate versus placebo found that flushing was a frequent event in the magnesium sulphate arm (percentage of flushing: 75% versus 7.7%, respectively; one study; 25 participants; low quality of evidence). AUTHORS' CONCLUSIONS: There is limited available evidence to determine the effects of non-pharmacological and pharmacological interventions in treating acute high altitude illness. Low-quality evidence suggests that dexamethasone and acetazolamide might reduce AMS score compared to placebo. However, the clinical benefits and harms related to these potential interventions remain unclear. Overall, the evidence is of limited practical significance in the clinical field. High-quality research in this field is needed, since most trials were poorly conducted and reported.

Sun protection for preventing basal cell and squamous cell skin cancers.

BACKGROUND: 'Keratinocyte cancer' is now the preferred term for the most commonly identified skin cancers basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (cSCC), which were previously commonly categorised as non-melanoma skin cancers (NMSC). Keratinocyte cancer (KC) represents about 95% of malignant skin tumours. Lifestyle changes have led to increased exposure to the sun, which has, in turn, led to a significant increase of new cases of KC, with a worldwide annual incidence of between 3% and 8%. The successful use of preventive measures could mean a significant reduction in the resources used by health systems, compared with the high cost of the treatment of these conditions. At present, there is no information about the quality of the evidence for the use of these sun protection strategies with an assessment of their benefits and risks. OBJECTIVES: To assess the effects of sun protection strategies (i.e. sunscreen and barrier methods) for preventing keratinocyte cancer (that is, basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (cSCC) of the skin) in the general population. SEARCH METHODS: We searched the following databases up to May 2016: the Cochrane Skin Group Specialised Register, CENTRAL, MEDLINE, Embase, and LILACS. We also searched five trial registries and the bibliographies of included studies for further references to relevant trials. SELECTION CRITERIA: We included randomised controlled clinical trials (RCTs) of preventive strategies for keratinocyte cancer, such as physical barriers and sunscreens, in the general population (children and adults), which may provide information about benefits and adverse events related to the use of solar protection measures. We did not include trials focused on educational strategies to prevent KC or preventive strategies in high-risk groups. Our prespecified primary outcomes were BCC or cSCC confirmed clinically or by histopathology at any follow-up and adverse events. DATA COLLECTION AND ANALYSIS: Two review authors independently selected studies for eligibility using Early Review Organizing Software (EROS). Similarly, two review authors independently used predesigned data collection forms to extract information from the original study reports about the participants, methods of randomisation, blinding, comparisons of interest, number of participants originally randomised by arm, follow-up losses, and outcomes, and they assessed the risk of bias. We resolved any disagreement by consulting a third author and contacted trial investigators of identified trials to obtain additional information. We used standard methodological procedures expected by Cochrane. MAIN RESULTS: We included one RCT (factorial design) that randomised 1621 participants.This study compared the daily application of sunscreen compared with discretionary use of sunscreen, with or without beta-carotene administration, in the general population. The study was undertaken in Australia; 55.2% of participants had fair skin, and they were monitored for 4.5 years for new cases of BCC or cSCC assessed by histopathology. We found this study to be at low risk of bias for domains such as allocation, blinding, and incomplete outcome data. However, we found multiple unclear risks related to other biases, including an unclear assessment of possible interactions between the effects of the different interventions evaluated (that is, sunscreen and beta-carotene). We found no difference in terms of the number of participants developing BCC (n = 1621; risk ratio (RR) 1.03, 95% confidence interval (CI) 0.74 to 1.43) or cSCC (n = 1621; RR 0.88, 95% CI 0.50 to 1.54) when comparing daily application of sunscreen with discretionary use, even when analyses were restricted to groups without beta-carotene supplementation. This evidence was of low quality, which means that there is some certainty that future studies may alter our confidence in this evidence.We reported adverse events in a narrative way and included skin irritation or contact allergy.We identified no studies that evaluated other sun protection measures, such as the use of sun-protective clothing, sunglasses, or hats, or seeking the shade when outdoors. AUTHORS' CONCLUSIONS: In this review, we assessed the effect of solar protection in preventing the occurrence of new cases of keratinocyte cancer. We only found one study that was suitable for inclusion. This was a study of sunscreens, so we were unable to assess any other forms of sun protection. The study addressed our prespecified primary outcomes, but not most of our secondary outcomes. We were unable to demonstrate from the available evidence whether sunscreen was effective for the prevention of basal cell carcinoma (BCC) or cutaneous squamous cell carcinoma (cSCC).Our certainty in the evidence was low because there was a lack of histopathological confirmation of BCC or cSCC in a significant percentage of cases. Amongst other sources of bias, it was not clear whether the study authors had assessed any interaction effects between the sunscreen and beta-carotene interventions. We think that further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.