Clinical relevance assessment of animal preclinical research (RAA) tool: development and explanation.

BACKGROUND: Only a small proportion of preclinical research (research performed in animal models prior to clinical trials in humans) translates into clinical benefit in humans. Possible reasons for the lack of translation of the results observed in preclinical research into human clinical benefit include the design, conduct, and reporting of preclinical studies. There is currently no formal domain-based assessment of the clinical relevance of preclinical research. To address this issue, we have developed a tool for the assessment of the clinical relevance of preclinical studies, with the intention of assessing the likelihood that therapeutic preclinical findings can be translated into improvement in the management of human diseases. METHODS: We searched the EQUATOR network for guidelines that describe the design, conduct, and reporting of preclinical research. We searched the references of these guidelines to identify further relevant publications and developed a set of domains and signalling questions. We then conducted a modified Delphi-consensus to refine and develop the tool. The Delphi panel members included specialists in evidence-based (preclinical) medicine specialists, methodologists, preclinical animal researchers, a veterinarian, and clinical researchers. A total of 20 Delphi-panel members completed the first round and 17 members from five countries completed all three rounds. RESULTS: This tool has eight domains (construct validity, external validity, risk of bias, experimental design and data analysis plan, reproducibility and replicability of methods and results in the same model, research integrity, and research transparency) and a total of 28 signalling questions and provides a framework for researchers, journal editors, grant funders, and regulatory authorities to assess the potential clinical relevance of preclinical animal research. CONCLUSION: We have developed a tool to assess the clinical relevance of preclinical studies. This tool is currently being piloted.

Assessment of assumptions of statistical analysis methods in randomised clinical trials: the what and how.

When analysing and presenting results of randomised clinical trials, trialists rarely report if or how underlying statistical assumptions were validated. To avoid data-driven biased trial results, it should be common practice to prospectively describe the assessments of underlying assumptions. In existing literature, there is no consensus on how trialists should assess and report underlying assumptions for the analyses of randomised clinical trials. With this study, we developed suggestions on how to test and validate underlying assumptions behind logistic regression, linear regression, and Cox regression when analysing results of randomised clinical trials.Two investigators compiled an initial draftbased on a review of the literature. Experienced statisticians and trialists from eight different research centres and trial units then participated in a anonymised consensus process, where we reached agreement on the suggestions presented in this paper.This paper provides detailed suggestions on 1) which underlying statistical assumptions behind logistic regression, multiple linear regression and Cox regression each should be assessed; 2) how these underlying assumptions may be assessed; and 3) what to do if these assumptions are violated.We believe that the validity of randomised clinical trial results will increase if our recommendations for assessing and dealing with violations of the underlying statistical assumptions are followed.

Methylphenidate for attention deficit hyperactivity disorder (ADHD) in children and adolescents - assessment of adverse events in non-randomised studies.

BACKGROUND: Attention deficit hyperactivity disorder (ADHD) is a common neurodevelopmental disorder in childhood. The psychostimulant methylphenidate is the most frequently used medication to treat it. Several studies have investigated the benefits of methylphenidate, showing possible favourable effects on ADHD symptoms, but the true magnitude of the effect is unknown. Concerning adverse events associated with the treatment, our systematic review of randomised clinical trials (RCTs) demonstrated no increase in serious adverse events, but a high proportion of participants suffered a range of non-serious adverse events. OBJECTIVES: To assess the adverse events associated with methylphenidate treatment for children and adolescents with ADHD in non-randomised studies. SEARCH METHODS: In January 2016, we searched CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL, 12 other databases and two trials registers. We also checked reference lists and contacted authors and pharmaceutical companies to identify additional studies. SELECTION CRITERIA: We included non-randomised study designs. These comprised comparative and non-comparative cohort studies, patient-control studies, patient reports/series and cross-sectional studies of methylphenidate administered at any dosage or formulation. We also included methylphenidate groups from RCTs assessing methylphenidate versus other interventions for ADHD as well as data from follow-up periods in RCTs. Participants had to have an ADHD diagnosis (from the 3rd to the 5th edition of the Diagnostic and Statistical Manual of Mental Disorders or the 9th or 10th edition of theInternational Classification of Diseases, with or without comorbid diagnoses. We required that at least 75% of participants had a normal intellectual capacity (intelligence quotient of more than 70 points) and were aged below 20 years. We excluded studies that used another ADHD drug as a co-intervention. DATA COLLECTION AND ANALYSIS: Fourteen review authors selected studies independently. Two review authors assessed risk of bias independently using the ROBINS-I tool for assessing risk of bias in non-randomised studies of interventions. All review authors extracted data. We defined serious adverse events according to the International Committee of Harmonization as any lethal, life-threatening or life-changing event. We considered all other adverse events to be non-serious adverse events and conducted meta-analyses of data from comparative studies. We calculated meta-analytic estimates of prevalence from non-comparative cohorts studies and synthesised data from patient reports/series qualitatively. We investigated heterogeneity by conducting subgroup analyses, and we also conducted sensitivity analyses. MAIN RESULTS: We included a total of 260 studies: 7 comparative cohort studies, 6 of which compared 968 patients who were exposed to methylphenidate to 166 controls, and 1 which assessed 1224 patients that were exposed or not exposed to methylphenidate during different time periods; 4 patient-control studies (53,192 exposed to methylphenidate and 19,906 controls); 177 non-comparative cohort studies (2,207,751 participants); 2 cross-sectional studies (96 participants) and 70 patient reports/series (206 participants). Participants' ages ranged from 3 years to 20 years. Risk of bias in the included comparative studies ranged from moderate to critical, with most studies showing critical risk of bias. We evaluated all non-comparative studies at critical risk of bias. The GRADE quality rating of the evidence was very low.Primary outcomesIn the comparative studies, methylphenidate increased the risk ratio (RR) of serious adverse events (RR 1.36, 95% confidence interval (CI) 1.17 to 1.57; 2 studies, 72,005 participants); any psychotic disorder (RR 1.36, 95% CI 1.17 to 1.57; 1 study, 71,771 participants); and arrhythmia (RR 1.61, 95% CI 1.48 to 1.74; 1 study, 1224 participants) compared to no intervention.In the non-comparative cohort studies, the proportion of participants on methylphenidate experiencing any serious adverse event was 1.20% (95% CI 0.70% to 2.00%; 50 studies, 162,422 participants). Withdrawal from methylphenidate due to any serious adverse events occurred in 1.20% (95% CI 0.60% to 2.30%; 7 studies, 1173 participants) and adverse events of unknown severity led to withdrawal in 7.30% of participants (95% CI 5.30% to 10.0%; 22 studies, 3708 participants).Secondary outcomesIn the comparative studies, methylphenidate, compared to no intervention, increased the RR of insomnia and sleep problems (RR 2.58, 95% CI 1.24 to 5.34; 3 studies, 425 participants) and decreased appetite (RR 15.06, 95% CI 2.12 to 106.83; 1 study, 335 participants).With non-comparative cohort studies, the proportion of participants on methylphenidate with any non-serious adverse events was 51.2% (95% CI 41.2% to 61.1%; 49 studies, 13,978 participants). These included difficulty falling asleep, 17.9% (95% CI 14.7% to 21.6%; 82 studies, 11,507 participants); headache, 14.4% (95% CI 11.3% to 18.3%; 90 studies, 13,469 participants); abdominal pain, 10.7% (95% CI 8.60% to 13.3%; 79 studies, 11,750 participants); and decreased appetite, 31.1% (95% CI 26.5% to 36.2%; 84 studies, 11,594 participants). Withdrawal of methylphenidate due to non-serious adverse events occurred in 6.20% (95% CI 4.80% to 7.90%; 37 studies, 7142 participants), and 16.2% were withdrawn for unknown reasons (95% CI 13.0% to 19.9%; 57 studies, 8340 participants). AUTHORS' CONCLUSIONS: Our findings suggest that methylphenidate may be associated with a number of serious adverse events as well as a large number of non-serious adverse events in children and adolescents, which often lead to withdrawal of methylphenidate. Our certainty in the evidence is very low, and accordingly, it is not possible to accurately estimate the actual risk of adverse events. It might be higher than reported here.Given the possible association between methylphenidate and the adverse events identified, it may be important to identify people who are most susceptible to adverse events. To do this we must undertake large-scale, high-quality RCTs, along with studies aimed at identifying responders and non-responders.

Simple, low-cost group-counselling programme vs treatment as usual for patients with newly notified occupational hand eczema-Exploratory analyses of effects on knowledge, behaviour and personal resources of the randomized PREVEX clinical trial.

BACKGROUND: Sickness absence in hand eczema patients has been associated with stress rather than disease severity, indicating that personal aspects regarding hand eczema should be investigated further. OBJECTIVES: To examine whether patient education vs treatment as usual can influence behaviour and knowledge regarding skin protection and care, as well as personal resources, in patients with occupational hand eczema. METHODS: PREVEX is an individually randomized clinical trial investigating the 1-year effects of a simple, low-cost group-counselling programme vs treatment as usual for patients with notified occupational hand eczema. Exploratory outcomes were behaviour, knowledge, self-efficacy, and self-evaluated skin care ability. RESULTS: In total, 1668 patients with notified occupational skin disease were invited to participate, of whom 769 were randomized and 756 were analysed: intervention group (n = 376) vs control group (n = 380). Behaviour was improved and the knowledge score increased in the intervention group as compared with the control group (respectively: estimate 0.08; 95%CI: 0.02-0.19; P = .01; and estimate 0.49; 95%CI: 0.28-0.70; P < .001). Self-efficacy was lower in the intervention group as compared with the control group (estimate -0.78; 95%CI: -1.25 to -0.30; P = .001). No difference was found regarding skin care abilities. CONCLUSIONS: The intervention had a positive influence on 1-year behaviour and knowledge, but was insufficient to result in long-term positive changes in personal resources regarding dealing with hand eczema.

Barriers to the conduct of randomised clinical trials within all disease areas.

BACKGROUND: Randomised clinical trials are key to advancing medical knowledge and to enhancing patient care, but major barriers to their conduct exist. The present paper presents some of these barriers. METHODS: We performed systematic literature searches and internal European Clinical Research Infrastructure Network (ECRIN) communications during face-to-face meetings and telephone conferences from 2013 to 2017 within the context of the ECRIN Integrating Activity (ECRIN-IA) project. RESULTS: The following barriers to randomised clinical trials were identified: inadequate knowledge of clinical research and trial methodology; lack of funding; excessive monitoring; restrictive privacy law and lack of transparency; complex regulatory requirements; and inadequate infrastructures. There is a need for more pragmatic randomised clinical trials conducted with low risks of systematic and random errors, and multinational cooperation is essential. CONCLUSIONS: The present paper presents major barriers to randomised clinical trials. It also underlines the value of using a pan-European-distributed infrastructure to help investigators overcome barriers for multi-country trials in any disease area.

EFFECTIVENESS OF DIALECTICAL BEHAVIOR THERAPY VERSUS COLLABORATIVE ASSESSMENT AND MANAGEMENT OF SUICIDALITY TREATMENT FOR REDUCTION OF SELF-HARM IN ADULTS WITH BORDERLINE PERSONALITY TRAITS AND DISORDER-A RANDOMIZED OBSERVER-BLINDED CLINICAL TRIAL.

BACKGROUND: Many psychological treatments have shown effect on reducing self-harm in adults with borderline personality disorder. There is a need of brief psychotherapeutical treatment alternative for suicide prevention in specialized outpatient clinics. METHODS/DESIGN: The DiaS trial was designed as a pragmatic single-center, two-armed, parallel-group observer-blinded, randomized clinical superiority trial. The participants had at least two criteria from the borderline personality disorder diagnosis and a recent suicide attempt (within a month). The participants were offered 16 weeks of dialectical behavior therapy (DBT) versus up to 16 weeks of collaborative assessment and management of suicidality (CAMS) treatment. The primary composite outcome was the number of participants with a new self-harm (nonsuicidal self-injury [NSSI] or suicide attempt) at week 28 from baseline. Other exploratory outcomes were: severity of borderline symptoms, depressive symptoms, hopelessness, suicide ideation, and self-esteem. RESULTS: At 28 weeks, the number of participants with new self-harm in the DBT group was 21 of 57 (36.8%) versus 12 of 51 (23.5%) in the CAMS treatment (OR: 1.90; 95% CI: 0.80-4.40; P = .14). When assessing the effect of DBT versus CAMS treatment on the individual components of the primary outcome, we observed no significant differences in the number of NSSI (OR: 1.60; 95% CI: 0.70-3.90; P = .31) or number of attempted suicides (OR: 2.24; 95% CI: 0.80-7.50; P = .12). CONCLUSION: In adults with borderline personality traits and disorder and a recent suicide attempt, DBT does not seem superior compared with CAMS for reduction of number of self-harm or suicide attempts. However, further randomized clinical trials may be needed.

Fostering EMA's transparency policy.

The European Medicines Agency has opened a window to access clinical trial data. This is an important step forward which deserves attention, support, and advice from all the stakeholders. Regulatory agencies are the most comprehensive repositories of clinical trial data on drugs and can also promote and develop standard practices for data sharing. The release of the EMA draft policy on publication and access to clinical trial data in 2013 has fueled a lively debate among academia, industry, and the public in general that is still ongoing. As clinical researchers and producers and users of clinical trial data, we endorse the European Medicines Agency's opening and offer a few suggestions for complete, safe, and effective data sharing.

The DiaS trial: dialectical behavior therapy versus collaborative assessment and management of suicidality on self-harm in patients with a recent suicide attempt and borderline personality disorder traits - study protocol for a randomized controlled trial.

BACKGROUND: In Denmark 8,000 to 10,000 people will attempt suicide each year. The Centre of Excellence in Suicide Prevention in the Capital Region of Denmark is treating patients with suicidal behavior, and a recent survey has shown that 30% of the patients are suffering from borderline personality disorder. The majority of patients (70% to 75%) with borderline personality disorder have a history of deliberate self-harm and 10% have a lifetime risk to die by suicide. The DiaS trial is comparing dialectical behavior therapy with collaborative assessment and management of suicidality-informed supportive psychotherapy, for the risk of repetition of deliberate self-harm in patients with a recent suicide attempt and personality traits within the spectrum of borderline personality disorder. Both treatments have previously shown effects in this group of patients on suicide ideation and self-harm compared with treatment as usual. METHODS/DESIGN: The trial is designed as a single-center, two-armed, parallel-group observer-blinded randomized clinical superiority trial. We will recruit 160 participants with a recent suicide attempt and at least two traits of the borderline personality disorder from the Centre of Excellence in Suicide Prevention, Capital Region of Denmark. Randomization will be performed though a centralized and computer-generated approach that conceals the randomization sequence. The interventions that are offered are a modified version of a dialectical behavior therapy program lasting 16 weeks versus collaborative assessment and management of suicidality-informed supportive psychotherapy, where the duration treatment will vary in accordance with established methods up to 16 weeks. The primary outcome measure is the ratio of deliberate self-harming acts including suicide attempts measured at week 28. Other exploratory outcomes are included such as severity of symptoms, suicide intention and ideation, depression, hopelessness, self-esteem, impulsivity, anger, and duration of respective treatments. TRIAL REGISTRATION: Clinical Trial.gov: NCT01512602.

A multi-centre phase IIa clinical study of predictive testing for preeclampsia: improved pregnancy outcomes via early detection (IMPROvED).

BACKGROUND: 5% of first time pregnancies are complicated by pre-eclampsia, the leading cause of maternal death in Europe. No clinically useful screening test exists; consequentially clinicians are unable to offer targeted surveillance or preventative strategies. IMPROvED Consortium members have pioneered a personalised medicine approach to identifying blood-borne biomarkers through recent technological advancements, involving mapping of the blood metabolome and proteome. The key objective is to develop a sensitive, specific, high-throughput and economically viable early pregnancy screening test for pre-eclampsia. METHODS/DESIGN: We report the design of a multicentre, phase IIa clinical study aiming to recruit 5000 low risk primiparous women to assess and refine innovative prototype tests based on emerging metabolomic and proteomic technologies. Participation involves maternal phlebotomy at 15 and 20 weeks' gestation, with optional testing and biobanking at 11 and 34 weeks. Blood samples will be analysed using two innovative, proprietary prototype platforms; one metabolomic based and one proteomic based, both of which outperform current biomarker based screening tests at comparable gestations. Analytical and clinical data will be collated and analysed via the Copenhagen Trials Unit. DISCUSSION: The IMPROvED study is expected to refine proteomic and metabolomic panels, combined with clinical parameters, and evaluate clinical applicability as an early pregnancy predictive test for pre-eclampsia. If 'at risk' patients can be identified, this will allow stratified care with personalised fetal and maternal surveillance, early diagnosis, timely intervention, and significant health economic savings. The IMPROvED biobank will be accessible to the European scientific community for high quality research into the cause and prevention of adverse pregnancy outcome. TRIAL REGISTRATION: Trial registration number NCT01891240The IMPROvED project is funded by the seventh framework programme for Research and Technological development of the EU. http://www.fp7-improved.eu/

Effect of comprehensive cardiac rehabilitation after heart valve surgery (CopenHeartVR): study protocol for a randomised clinical trial.

BACKGROUND: Heart valve diseases are common with an estimated prevalence of 2.5% in the Western world. The number is rising due to an ageing population. Once symptomatic, heart valve diseases are potentially lethal, and heavily influence daily living and quality of life. Surgical treatment, either valve replacement or repair, remains the treatment of choice. However, post surgery, the transition to daily living may become a physical, mental and social challenge. We hypothesise that a comprehensive cardiac rehabilitation programme can improve physical capacity and self-assessed mental health and reduce hospitalisation and healthcare costs after heart valve surgery. METHODS: A randomised clinical trial, CopenHeartVR, aims to investigate whether cardiac rehabilitation in addition to usual care is superior to treatment as usual after heart valve surgery. The trial will randomly allocate 210 patients, 1:1 intervention to control group, using central randomisation, and blinded outcome assessment and statistical analyses. The intervention consists of 12 weeks of physical exercise, and a psycho-educational intervention comprising five consultations. Primary outcome is peak oxygen uptake (VO2 peak) measured by cardiopulmonary exercise testing with ventilatory gas analysis. Secondary outcome is self-assessed mental health measured by the standardised questionnaire Short Form 36. Also, long-term healthcare utilisation and mortality as well as biochemistry, echocardiography and cost-benefit will be assessed. A mixed-method design is used to evaluate qualitative and quantitative findings encompassing a survey-based study before the trial and a qualitative pre- and post-intervention study. DISCUSSION: The study is approved by the local regional Research Ethics Committee (H-1-2011-157), and the Danish Data Protection Agency (j.nr. 2007-58-0015). TRIAL REGISTRATION: ClinicalTrials.gov (http://NCT01558765).

Treatment in a specialised out-patient mood disorder clinic v. standard out-patient treatment in the early course of bipolar disorder: randomised clinical trial.

BACKGROUND: Little is known about whether treatment in a specialised out-patient mood disorder clinic improves long-term prognosis for patients discharged from initial psychiatric hospital admissions for bipolar disorder. AIMS: To assess the effect of treatment in a specialised out-patient mood disorder clinic v. standard decentralised psychiatric treatment among patients discharged from one of their first three psychiatric hospital admissions for bipolar disorder. METHOD: Patients discharged from their first, second or third hospital admission with a single manic episode or bipolar disorder were randomised to treatment in a specialised out-patient mood disorder clinic or standard care (ClinicalTrials.gov: NCT00253071). The primary outcome measure was readmission to hospital, which was obtained from the Danish Psychiatric Central Register. RESULTS: A total of 158 patients with mania/bipolar disorder were included. The rate of readmission to hospital was significantly decreased for patients treated in the mood disorder clinic compared with standard treatment (unadjusted hazard ratio 0.60, 95% CI 0.37-0.97, P = 0.034). Patients treated in the mood disorder clinic more often used a mood stabiliser or an antipsychotic and satisfaction with treatment was more prevalent than among patients who received standard care. CONCLUSIONS: Treatment in a specialised mood disorder clinic early in the course of bipolar disorder substantially reduces readmission to a psychiatric hospital and increases satisfaction with care.

Typical investigational medicinal products follow relatively uniform regulations in 10 European Clinical Research Infrastructures Network (ECRIN) countries.

BACKGROUND: In order to facilitate multinational clinical research, regulatory requirements need to become international and harmonised. The EU introduced the Directive 2001/20/EC in 2004, regulating investigational medicinal products in Europe. METHODS: We conducted a survey in order to identify the national regulatory requirements for major categories of clinical research in ten European Clinical Research Infrastructures Network (ECRIN) countries-Austria, Denmark, France, Germany, Hungary, Ireland, Italy, Spain, Sweden, and United Kingdom-covering approximately 70% of the EU population. Here we describe the results for regulatory requirements for typical investigational medicinal products, in the ten countries. RESULTS: Our results show that the ten countries have fairly harmonised definitions of typical investigational medicinal products. Clinical trials assessing typical investigational medicinal products require authorisation from a national competent authority in each of the countries surveyed. The opinion of the competent authorities is communicated to the trial sponsor within the same timelines, i.e., no more than 60 days, in all ten countries. The authority to which the application has to be sent to in the different countries is not fully harmonised. CONCLUSION: The Directive 2001/20/EC defined the term 'investigational medicinal product' and all regulatory requirements described therein are applicable to investigational medicinal products. Our survey showed, however, that those requirements had been adopted in ten European countries, not for investigational medicinal products overall, but rather a narrower category which we term 'typical' investigational medicinal products. The result is partial EU harmonisation of requirements and a relatively navigable landscape for the sponsor regarding typical investigational medicinal products.

Comparison of statistical inferences from the DerSimonian-Laird and alternative random-effects model meta-analyses - an empirical assessment of 920 Cochrane primary outcome meta-analyses.

In random-effects model meta-analysis, the conventional DerSimonian-Laird (DL) estimator typically underestimates the between-trial variance. Alternative variance estimators have been proposed to address this bias. This study aims to empirically compare statistical inferences from random-effects model meta-analyses on the basis of the DL estimator and four alternative estimators, as well as distributional assumptions (normal distribution and t-distribution) about the pooled intervention effect. We evaluated the discrepancies of p-values, 95% confidence intervals (CIs) in statistically significant meta-analyses, and the degree (percentage) of statistical heterogeneity (e.g. I(2)) across 920 Cochrane primary outcome meta-analyses. In total, 414 of the 920 meta-analyses were statistically significant with the DL meta-analysis, and 506 were not. Compared with the DL estimator, the four alternative estimators yielded p-values and CIs that could be interpreted as discordant in up to 11.6% or 6% of the included meta-analyses pending whether a normal distribution or a t-distribution of the intervention effect estimates were assumed. Large discrepancies were observed for the measures of degree of heterogeneity when comparing DL with each of the four alternative estimators. Estimating the degree (percentage) of heterogeneity on the basis of less biased between-trial variance estimators seems preferable to current practice. Disclosing inferential sensitivity of p-values and CIs may also be necessary when borderline significant results have substantial impact on the conclusion. Copyright © 2012 John Wiley & Sons, Ltd.

The Best Bypass Surgery Trial: rationale and design of a randomized clinical trial with blinded outcome assessment of conventional versus off-pump coronary artery bypass grafting.

BACKGROUND: Recent trials suggest that off-pump coronary artery bypass grafting (OPCAB) reduces the risk of mortality and morbidity compared with conventional coronary artery bypass grafting (CCAB) using cardiopulmonary bypass. Patients with a moderate- to high-risk of complications after CCAB may have additional benefit from OPCAB. METHODS: The Best Bypass Surgery Trial is a randomized, single center trial comparing the effects of OPCAB versus CCAB. The inclusion criteria are 3 vessel coronary heart disease affecting one of the marginal arteries, age>54 years, and EuroSCORE>or=5. The primary composite outcome measure consists of all-cause mortality, myocardial infarction, stroke, cardiac arrest, cardiogenic shock, and cardiac revascularization procedure. Follow up involves collection of data of mortality and morbidity via linkage to public registers, quality of life assessment at 3 and 12 months postoperatively and angiographic control at 12 months. The sample size of 330 patients was based on an estimated 75% one-year event free rate of the primary outcome measure in the OPCAB arm and 60% in the control arm with alpha=.05 and beta=.20. Accordingly, the trial will be able to detect an absolute risk reduction of 15% or a relative risk reduction of 37.5%. The median follow-up time is scheduled to 3 years. RESULTS: Enrollment started in April 2002 and ended March 2006. CONCLUSION: The results may have implications on the treatment modality of moderate- to high-risk patients scheduled for coronary artery bypass grafting.

Association of funding and conclusions in randomized drug trials: a reflection of treatment effect or adverse events?

CONTEXT: Previous studies indicate that industry-sponsored trials tend to draw proindustry conclusions. OBJECTIVE: To explore whether the association between funding and conclusions in randomized drug trials reflects treatment effects or adverse events. DESIGN: Observational study of 370 randomized drug trials included in meta-analyses from Cochrane reviews selected from the Cochrane Library, May 2001. From a random sample of 167 Cochrane reviews, 25 contained eligible meta-analyses (assessed a binary outcome; pooled at least 5 full-paper trials of which at least 1 reported adequate and 1 reported inadequate allocation concealment). The primary binary outcome from each meta-analysis was considered the primary outcome for all trials included in each meta-analysis. The association between funding and conclusions was analyzed by logistic regression with adjustment for treatment effect, adverse events, and additional confounding factors (methodological quality, control intervention, sample size, publication year, and place of publication). MAIN OUTCOME MEASURE: Conclusions in trials, classified into whether the experimental drug was recommended as the treatment of choice or not. RESULTS: The experimental drug was recommended as treatment of choice in 16% of trials funded by nonprofit organizations, 30% of trials not reporting funding, 35% of trials funded by both nonprofit and for-profit organizations, and 51% of trials funded by for-profit organizations (P<.001; chi2 test). Logistic regression analyses indicated that funding, treatment effect, and double blinding were the only significant predictors of conclusions. Adjusted analyses showed that trials funded by for-profit organizations were significantly more likely to recommend the experimental drug as treatment of choice (odds ratio, 5.3; 95% confidence interval, 2.0-14.4) compared with trials funded by nonprofit organizations. This association did not appear to reflect treatment effect or adverse events. CONCLUSIONS: Conclusions in trials funded by for-profit organizations may be more positive due to biased interpretation of trial results. Readers should carefully evaluate whether conclusions in randomized trials are supported by data.