Jos Kleijnen

The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate health care interventions: explanation and elaboration.

Alessandro Liberati and colleagues present an Explanation and Elaboration of the PRISMA Statement, updated guidelines for the reporting of systematic reviews and meta-analyses.

Cannabinoids for Medical Use: A Systematic Review and Meta-analysis

IMPORTANCE Cannabis and cannabinoid drugs are widely used to treat disease or alleviate symptoms, but their efficacy for specific indications is not clear. OBJECTIVE To conduct a systematic review of the benefits and adverse events (AEs) of cannabinoids. DATA SOURCES Twenty-eight databases from inception to April 2015. STUDY SELECTION Randomized clinical trials of cannabinoids for the following indications: nausea and vomiting due to chemotherapy, appetite stimulation in HIV/AIDS, chronic pain, spasticity due to multiple sclerosis or paraplegia, depression, anxiety disorder, sleep disorder, psychosis, glaucoma, or Tourette syndrome. DATA EXTRACTION AND SYNTHESIS Study quality was assessed using the Cochrane risk of bias tool. All review stages were conducted independently by 2 reviewers. Where possible, data were pooled using random-effects meta-analysis. MAIN OUTCOMES AND MEASURES Patient-relevant/disease-specific outcomes, activities of daily living, quality of life, global impression of change, and AEs. RESULTS A total of 79 trials (6462 participants) were included; 4 were judged at low risk of bias. Most trials showed improvement in symptoms associated with cannabinoids but these associations did not reach statistical significance in all trials. Compared with placebo, cannabinoids were associated with a greater average number of patients showing a complete nausea and vomiting response (47% vs 20%; odds ratio [OR], 3.82 [95% CI, 1.55-9.42]; 3 trials), reduction in pain (37% vs 31%; OR, 1.41 [95% CI, 0.99-2.00]; 8 trials), a greater average reduction in numerical rating scale pain assessment (on a 0-10-point scale; weighted mean difference [WMD], -0.46 [95% CI, -0.80 to -0.11]; 6 trials), and average reduction in the Ashworth spasticity scale (WMD, -0.36 [95% CI, -0.69 to -0.05]; 7 trials). There was an increased risk of short-term AEs with cannabinoids, including serious AEs. Common AEs included dizziness, dry mouth, nausea, fatigue, somnolence, euphoria, vomiting, disorientation, drowsiness, confusion, loss of balance, and hallucination. CONCLUSIONS AND RELEVANCE There was moderate-quality evidence to support the use of cannabinoids for the treatment of chronic pain and spasticity. There was low-quality evidence suggesting that cannabinoids were associated with improvements in nausea and vomiting due to chemotherapy, weight gain in HIV infection, sleep disorders, and Tourette syndrome. Cannabinoids were associated with an increased risk of short-term AEs.

Epidemiology of chronic non-cancer pain in Europe: narrative review of prevalence, pain treatments and pain impact.

Abstract Background: Estimates on the epidemiology of chronic non-cancer pain vary widely throughout Europe. It is unclear whether this variation reflects true population differences or methodological factors. Such epidemiological information supports European decision makers in allocating healthcare resources. Objective: Pan-Europe epidemiological data about chronic non-cancer pain was obtained using systematic review principles in searching and summarising results. Methods: Multiple databases (MEDLINE, EMBASE, Cochrane Library, CRD Databases, and GIN) were systematically searched for primary studies containing epidemiological data on chronic non-cancer pain in Europe excluding studies that solely concerned migraines, headaches and pain associated with specific disease conditions. The studies were prioritised according to quality, recency and validity. Main outcomes: Eighteen research questions concerning aspects of chronic pain included: prevalence; incidence; pain treatments, control and compliance; treatment satisfaction; and quality of life and economic impacts. Results: The search yielded 16 619 references and 45 were relevant to Europe. Studies for each question were selected that provided the most recent, representative and valid data. There was a clear lack of studies concerning chronic non-cancer pain in Europe as a whole. The 1-month prevalence of moderate-to-severe non-cancer chronic pain was 19%. Chronic pain significantly impacted on patient-perceived health status, affected everyday activities including economic pursuits and personal relationships, and was significantly associated with depressive symptoms. The majority relied on drugs for pain control and NSAIDs were the most frequent drug choice. Despite pain medications, a large proportion had inadequate pain control. Conclusion: To the authors’ knowledge this is the most comprehensive literature review on epidemiological data in this field. It is clear that chronic pain has a dramatic impact on European society. Since chronic non-cancer pain is treated differently from cancer-related pain, the lack of data in this area clearly underlines the need for decision makers in healthcare to gather further epidemiological data.

ROBIS: A new tool to assess risk of bias in systematic reviews was developed

Objective To develop ROBIS, a new tool for assessing the risk of bias in systematic reviews (rather than in primary studies). Study Design and Setting We used four-stage approach to develop ROBIS: define the scope, review the evidence base, hold a face-to-face meeting, and refine the tool through piloting. Results ROBIS is currently aimed at four broad categories of reviews mainly within health care settings: interventions, diagnosis, prognosis, and etiology. The target audience of ROBIS is primarily guideline developers, authors of overviews of systematic reviews (“reviews of reviews”), and review authors who might want to assess or avoid risk of bias in their reviews. The tool is completed in three phases: (1) assess relevance (optional), (2) identify concerns with the review process, and (3) judge risk of bias. Phase 2 covers four domains through which bias may be introduced into a systematic review: study eligibility criteria; identification and selection of studies; data collection and study appraisal; and synthesis and findings. Phase 3 assesses the overall risk of bias in the interpretation of review findings and whether this considered limitations identified in any of the phase 2 domains. Signaling questions are included to help judge concerns with the review process (phase 2) and the overall risk of bias in the review (phase 3); these questions flag aspects of review design related to the potential for bias and aim to help assessors judge risk of bias in the review process, results, and conclusions. Conclusions ROBIS is the first rigorously developed tool designed specifically to assess the risk of bias in systematic reviews.

Differential Effectiveness of Placebo Treatments: A Systematic Review of Migraine Prophylaxis

IMPORTANCE When analyzing results of randomized clinical trials, the treatment with the greatest specific effect compared with its placebo control is considered to be the most effective one. Although systematic variations of improvements in placebo control groups would have important implications for the interpretation of placebo-controlled trials, the knowledge base on the subject is weak. OBJECTIVE To investigate whether different types of placebo treatments are associated with different responses using the studies of migraine prophylaxis for this analysis. DESIGN, SETTING, AND PARTICIPANTS We searched relevant sources through February 2012 and contacted the authors to identify randomized clinical trials on the prophylaxis of migraine with an observation period of at least 8 weeks after randomization that compared an experimental treatment with a placebo control group. We calculated pooled random-effects estimates according to the type of placebo for the proportions of treatment response. We performed meta-regression analyses to identify sources of heterogeneity. In a network meta-analysis, direct and indirect comparisons within and across trials were combined. Additional analyses were performed for continuous outcomes. EXPOSURE Active migraine treatment and the placebo control conditions. MAIN OUTCOMES AND MEASURES Proportion of treatment responders, defined as having an attack frequency reduction of at least 50%. Other available outcomes in order of preference included a reduction of 50% or greater in migraine days, the number of headache days, or headache score or a significant improvement as assessed by the patients or their physicians. RESULTS Of the 102 eligible trials, 23 could not be included in the meta-analyses owing to insufficient data. Sham acupuncture (proportion of responders, 0.38 [95% CI, 0.30-0.47]) and sham surgery (0.58 [0.37-0.77]) were associated with a more pronounced reduction of migraine frequency than oral pharmacological placebos (0.22 [0.17-0.28]) and were the only significant predictors of response in placebo groups in multivariable analyses (P = .005 and P = .001, respectively). Network meta-analysis confirmed that more patients reported response in sham acupuncture groups than in oral pharmacological placebo groups (odds ratio, 1.88 [95% CI, 1.30-2.72]). Corresponding analyses for continuous outcomes showed similar findings. CONCLUSIONS AND RELEVANCE Sham acupuncture and sham surgery are associated with higher responder ratios than oral pharmacological placebos. Clinicians who treat patients with migraine should be aware that a relevant part of the overall effect they observe in practice might be due to nonspecific effects and that the size of such effects might differ between treatment modalities.

Chronic Diseases in the European Union: The Prevalence and Health Cost Implications of Chronic Pain

ABSTRACT The objective of this study was to assess recent data on the prevalence of chronic pain as part of chronic diseases; the prevalence of chronic pain as a chronic condition in its own right; the costs attributed to chronic pain; and the European Union (EU) policies to addressing chronic pain. Recent literature was reviewed for data on the prevalence and cost implications of chronic pain in the EU. Following on from an earlier systematic review, 8 databases were searched for prevalence and 10 for cost information from 2009 to 2011 and relevant EU organizations were contacted. Ten cost and 29 prevalence studies were included from the 142 full papers screened. The general adult population reported an average chronic pain prevalence of 27%, which was similar to those for common chronic conditions. Fibromyalgia had the highest unemployment rate (6%; Rivera et al., Clin Exp Rheumatol. 2009;27[Suppl 56]:S39–S45) claims for incapacity benefit (up to 29.9%; Sicras-Mainar et al., Arthritis Res Ther. 2009;11:R54), and greatest number of days of absence from work (Rivera et al., Clin Exp Rheumatol. 2009;27[Suppl 56]:S39–S45). Chronic pain is common and the total population cost is high. Despite its high impact, chronic pain as a condition seems to have had little specific policy response. However, there does appear to be sufficient evidence to at least make addressing chronic pain a high priority alongside other chronic diseases as well as to conduct more research, particularly regarding cost.

Systematic review of tapentadol in chronic severe pain

Abstract Aim: A systematic review of chronic pain treatment with strong opioids (step 3 WHO pain ladder) and a comparison to a new drug recently approved for the treatment of severe chronic pain in Europe, tapentadol (Palexia, Nucynta *Co-manufactured. Palexia is a registered trade name of Grünenthal, Aachen Germany. Nucynta is a registered trade name of Johnson and Johnson, New Brunswick, NJ, USA.), were performed. Methods: Thirteen electronic databases were searched as well as a number of other sources from 1980 up to November 2010 for relevant randomized controlled clinical trials in chronic moderate and severe pain investigating at least one step 3 opioid. Chronic pain could be nociceptive or neuropathic, malignant or non-malignant, all systemic administrations were considered as well as trials of different lengths. Two separate analyses were performed, one only for trials which reported (at least as sub-groups) the outcome in patients with severe pain, the other including both moderate and severe pain conditions. With the exception of the direct comparison between tapentadol, oxycodone and placebo, indirect comparisons were performed based on a network analysis. Trials with an enriched or an enriched withdrawal design were excluded. Primary (pain intensity) and a number of secondary endpoints were evaluated, including pain relief (30% and 50%), patient global impression of change, quality of life, quality of sleep, discontinuations, as well as serious adverse events and selected adverse events. Results: Only 10 trials were eligible for analysis of patients with severe pain (eight investigating tapentadol and two trials comparing buprenorphine patch vs placebo). For moderate and severe pain, 42 relevant trials were identified and indirect comparisons with transdermal buprenorphine, transdermal fentanyl, hydromorphone, morphine, and oxymorphone were performed. This report focuses on the network analysis. Tapentadol showed statistically favourable results over oxycodone for pain intensity, 30% and 50% pain relief, patient global impression of change (PGIC), and quality of life. Furthermore, some of the most important adverse events of chronic opioid treatment were significantly less frequent with tapentadol as compared to oxycodone, i.e. constipation, nausea, and vomiting; discontinuations due to these adverse events were found significantly reduced with tapentadol. Similar results were obtained for the network analysis, i.e. tapentadol was superior for the primary outcome (pain intensity) to hydromorphone and morphine, whereas fentanyl and oxymorphone showed trends in favour of these treatments. Significantly less frequent gastrointestinal adverse events of tapentadol were observed in comparison with fentanyl, hydromorphone, morphine, and oxymorphone, apparently leading to significantly reduced treatment discontinuations (for any reason). Conclusions: Taken together, the benefit–risk ratio of tapentadol appears to be improved compared to step 3 opioids.

Fetal umbilical artery Doppler to predict compromise of fetal/neonatal wellbeing in a high‐risk population: systematic review and bivariate meta‐analysis

We investigated the accuracy of fetal umbilical artery Doppler to predict the risk of compromise of fetal/neonatal wellbeing in a high‐risk population.

Systematic Review of topotecan (Hycamtin) in relapsed small cell lung cancer

BackgroundTo undertake a systematic review of the available data for oral and intravenous topotecan in adults with relapsed small cell lung cancer (SCLC) for whom re-treatment with the first line regimen is not considered appropriate.MethodsWe searched six databases from 1980 up to March 2009 for relevant trials regardless of language or publication status. Relevant studies included any randomised trial of any chemotherapeutic treatment against any comparator in this licensed indication. Where possible we used apposite quantitative methods. Where meta-analysis was considered unsuitable for some or all of the data, we employed a narrative synthesis method. For indirect comparisons we used the method of Bucher et al., where available data allowed it, otherwise we used narrative descriptions.ResultsSeven unique studies met the inclusion criteria, four of which could be used in our analyses. These included one study comparing oral topotecan plus best supportive care (BSC) to BSC alone, one study comparing intravenous topotecan to cyclophosphamide, adriamycin and vincristine (CAV), and two studies comparing oral topotecan with intravenous topotecan. All four studies appear to be well conducted and with low risk of bias.Oral topotecan plus BSC has advantages over BSC alone in terms of survival (hazard ratio = 0.61; 95% CI, 0.43 to 0.87) and quality of life (EQ-5 D difference: 0.15; 95% CI, 0.05 to 0.25). Intravenous topotecan was at least as effective as CAV in the treatment of patients with recurrent small-cell lung cancer and resulted in improved quality-of-life with respect to several symptoms.CAV was associated with significantly less grade 4 thrombocytopenia compared with IV topotecan (risk ratio = 5.83; 95% CI, 2.35 to 14.42). Survival (hazard ratio = 0.98; 95% CI, 0.77 to 1.25) and response (pooled risk ratio = 1.04; 95% CI, 0.58 to 1.85) data were similar for the oral and IV topotecan groups. Symptom control was also very similar between the trials and between the oral and IV groups. Toxicity data showed a significant difference in favour of oral topotecan for neutropenia (pooled risk ratio = 0.65; 95% CI, 0.47 to 0.89).Indirect evidence showed that oral topotecan was at least as good as or better than CAV on all outcomes (survival, response rates, toxicities, and symptoms) that allowed indirect comparisons, with the only exception being grade four thrombocytopenia which occurred less often on CAV treatment.ConclusionsConcerning topotecan both the oral and intravenous options have similar efficacy, and patient preference may be a decisive factor if the choice would be between the two formulations. The best trial evidence for decision making, because it was tested versus best supportive care, exists for oral topotecan. Indirectly, because we have two head-to-head comparisons of oral versus intravenous topotecan, and one comparison of intravenous topotecan versus CAV in similar patients as in the trial against best supportive care, one might infer that IV topotecan and CAV could also be superior to best supportive care, and that oral topotecan has similar effects to CAV with possibly better symptom control. From the evidence discussed above, it is evident that oral topotecan has similar efficacy to IV topotecan (direct comparison) and CAV (indirect comparison). There is no further evidence base of direct or possible indirect comparisons for other comparators than CAV of either oral or IV topotecan.

Evidence-informed recommendations to reduce dissemination bias in clinical research: conclusions from the OPEN (Overcome failure to Publish nEgative fiNdings) project based on an international consensus meeting

Background Dissemination bias in clinical research severely impedes informed decision-making not only for healthcare professionals and patients, but also for funders, research ethics committees, regulatory bodies and other stakeholder groups that make health-related decisions. Decisions based on incomplete and biased evidence cannot only harm people, but may also have huge financial implications by wasting resources on ineffective or harmful diagnostic and therapeutic measures, and unnecessary research. Owing to involvement of multiple stakeholders, it remains easy for any single group to assign responsibility for resolving the problem to others. Objective To develop evidence-informed general and targeted recommendations addressing the various stakeholders involved in knowledge generation and dissemination to help overcome the problem of dissemination bias on the basis of previously collated evidence. Methods Based on findings from systematic reviews, document analyses and surveys, we developed general and targeted draft recommendations. During a 2-day workshop in summer 2013, these draft recommendations were discussed with external experts and key stakeholders, and refined following a rigorous and transparent methodological approach. Results Four general, overarching recommendations applicable to all or most stakeholder groups were formulated, addressing (1) awareness raising, (2) implementation of targeted recommendations, (3) trial registration and results posting, and (4) systematic approaches to evidence synthesis. These general recommendations are complemented and specified by 47 targeted recommendations tailored towards funding agencies, pharmaceutical and device companies, research institutions, researchers (systematic reviewers and trialists), research ethics committees, trial registries, journal editors and publishers, regulatory agencies, benefit (health technology) assessment institutions and legislators. Conclusions Despite various recent examples of dissemination bias and several initiatives to reduce it, the problem of dissemination bias has not been resolved. Tailored recommendations based on a comprehensive approach will hopefully help increase transparency in biomedical research by overcoming the failure to disseminate negative findings.