Ignacio Neumann

Prevalence, Characteristics, and Publication of Discontinued Randomized Trials

IMPORTANCE The discontinuation of randomized clinical trials (RCTs) raises ethical concerns and often wastes scarce research resources. The epidemiology of discontinued RCTs, however, remains unclear. OBJECTIVES To determine the prevalence, characteristics, and publication history of discontinued RCTs and to investigate factors associated with RCT discontinuation due to poor recruitment and with nonpublication. DESIGN AND SETTING Retrospective cohort of RCTs based on archived protocols approved by 6 research ethics committees in Switzerland, Germany, and Canada between 2000 and 2003. We recorded trial characteristics and planned recruitment from included protocols. Last follow-up of RCTs was April 27, 2013. MAIN OUTCOMES AND MEASURES Completion status, reported reasons for discontinuation, and publication status of RCTs as determined by correspondence with the research ethics committees, literature searches, and investigator surveys. RESULTS After a median follow-up of 11.6 years (range, 8.8-12.6 years), 253 of 1017 included RCTs were discontinued (24.9% [95% CI, 22.3%-27.6%]). Only 96 of 253 discontinuations (37.9% [95% CI, 32.0%-44.3%]) were reported to ethics committees. The most frequent reason for discontinuation was poor recruitment (101/1017; 9.9% [95% CI, 8.2%-12.0%]). In multivariable analysis, industry sponsorship vs investigator sponsorship (8.4% vs 26.5%; odds ratio [OR], 0.25 [95% CI, 0.15-0.43]; P < .001) and a larger planned sample size in increments of 100 (-0.7%; OR, 0.96 [95% CI, 0.92-1.00]; P = .04) were associated with lower rates of discontinuation due to poor recruitment. Discontinued trials were more likely to remain unpublished than completed trials (55.1% vs 33.6%; OR, 3.19 [95% CI, 2.29-4.43]; P < .001). CONCLUSIONS AND RELEVANCE In this sample of trials based on RCT protocols from 6 research ethics committees, discontinuation was common, with poor recruitment being the most frequently reported reason. Greater efforts are needed to ensure the reporting of trial discontinuation to research ethics committees and the publication of results of discontinued trials.

Decision aids that really promote shared decision making: the pace quickens

Decision aids can help shared decision making, but most have been hard to produce, onerous to update, and are not being used widely. Thomas Agoritsas and colleagues explore why and describe a new electronic model that holds promise of being more useful for clinicians and patients to use together at the point of care

World Health Organization recommendations are often strong based on low confidence in effect estimates

OBJECTIVES Expert guideline panelists are sometimes reluctant to offer weak/conditional/contingent recommendations. Grading of Recommendations Assessment, Development and Evaluation (GRADE) guidance warns against strong recommendations when confidence in effect estimates is low or very low, suggesting that such recommendations may seldom be justified. We aim to characterize the classification of strength of recommendations and confidence in estimates in World Health Organization (WHO) guidelines that used the GRADE approach and graded both strength and confidence (GRADEd). STUDY DESIGN AND SETTING We reviewed all WHO guidelines (January 2007 to December 2012), identified those that were GRADEd, and, in these, examined the classifications of strong and weak and associated confidence in estimates (high, moderate, low, and very low). RESULTS We identified 116 WHO guidelines in which 43 (37%) were GRADEd and had 456 recommendations, of which 289 (63.4%) were strong and 167 (36.6%) were conditional/weak. Of the 289 strong recommendations, 95 (33.0%) were based on evidence warranting low confidence in estimates and 65 (22.5%) on evidence warranting very low confidence in estimates (55.5% strong recommendations overall based on low or very low confidence in estimates). CONCLUSION Strong recommendations based on low or very low confidence estimates are very frequently made in WHO guidelines. Further study to determine the reasons for such high uncertainty recommendations is warranted.

Oral direct Factor Xa inhibitors versus low-molecular-weight heparin to prevent venous thromboembolism in patients undergoing total hip or knee replacement: a systematic review and meta-analysis.

BACKGROUND Thromboembolic disease is the most frequent medical complication of arthroplasty. PURPOSE To evaluate the benefits and harms of oral direct factor Xa inhibitors versus low-molecular-weight heparin (LMWH) in patients undergoing total hip or knee replacement. DATA SOURCES MEDLINE (1966 to December 2011), EMBASE (1980 to December 2011), and the Cochrane Central Register of Controlled Trials (up to December 2011), without language restrictions. References of reviews and abstracts of conferences were hand-searched. STUDY SELECTION Randomized trials in patients undergoing hip or knee replacement that evaluated factor Xa inhibitors versus LMWH. DATA EXTRACTION Two reviewers independently evaluated eligibility, abstracted the data, and assessed risk for bias. DATA SYNTHESIS In 22 trials, high-quality evidence indicated that the absolute effect of factor Xa inhibitors and LMWH does not differ in terms of all-cause mortality (risk difference, 0 fewer deaths per 1000 patients [95% CI, 2 fewer to 1 more death]) or nonfatal pulmonary embolism (risk difference, 0 fewer events per 1000 patients [CI, 1 fewer to 2 more events]). Factor Xa inhibitors can prevent 4 instances of symptomatic deep venous thrombosis per 1000 treated patients (CI, 3 to 6 fewer events; high-quality evidence) but may increase major bleeding by 2 more events per 1000 patients (CI, 0 to 4 more events; moderate-quality evidence). High, but not lower, doses of oral factor Xa inhibitors increased bleeding compared with LMWH. LIMITATIONS Most trials did not report outcome data for a substantial proportion of the patients. In 9 trials, the follow-up period was 14 days or less. CONCLUSION Compared with LMWH, lower doses of oral factor Xa inhibitors can achieve a small absolute risk reduction in symptomatic deep venous thrombosis without increasing bleeding.

Subgroup analyses in randomised controlled trials: cohort study on trial protocols and journal publications

Objective To investigate the planning of subgroup analyses in protocols of randomised controlled trials and the agreement with corresponding full journal publications. Design Cohort of protocols of randomised controlled trial and subsequent full journal publications. Setting Six research ethics committees in Switzerland, Germany, and Canada. Data sources 894 protocols of randomised controlled trial involving patients approved by participating research ethics committees between 2000 and 2003 and 515 subsequent full journal publications. Results Of 894 protocols of randomised controlled trials, 252 (28.2%) included one or more planned subgroup analyses. Of those, 17 (6.7%) provided a clear hypothesis for at least one subgroup analysis, 10 (4.0%) anticipated the direction of a subgroup effect, and 87 (34.5%) planned a statistical test for interaction. Industry sponsored trials more often planned subgroup analyses compared with investigator sponsored trials (195/551 (35.4%) v 57/343 (16.6%), P<0.001). Of 515 identified journal publications, 246 (47.8%) reported at least one subgroup analysis. In 81 (32.9%) of the 246 publications reporting subgroup analyses, authors stated that subgroup analyses were prespecified, but this was not supported by 28 (34.6%) corresponding protocols. In 86 publications, authors claimed a subgroup effect, but only 36 (41.9%) corresponding protocols reported a planned subgroup analysis. Conclusions Subgroup analyses are insufficiently described in the protocols of randomised controlled trials submitted to research ethics committees, and investigators rarely specify the anticipated direction of subgroup effects. More than one third of statements in publications of randomised controlled trials about subgroup prespecification had no documentation in the corresponding protocols. Definitive judgments regarding credibility of claimed subgroup effects are not possible without access to protocols and analysis plans of randomised controlled trials.

World Health Organization strong recommendations based on low-quality evidence (study quality) are frequent and often inconsistent with GRADE guidance

OBJECTIVES In 2007 the World Health Organization (WHO) adopted the GRADE system for development of public health guidelines. Previously we found that many strong recommendations issued by WHO are based on evidence for which there is only low or very low confidence in the estimates of effect (discordant recommendations). GRADE guidance indicates that such discordant recommendations are rarely appropriate but suggests five paradigmatic situations in which discordant recommendations may be warranted. We sought to provide insight into the many discordant recommendations in WHO guidelines. STUDY DESIGN AND SETTING We examined all guidelines that used the GRADE method and were approved by the WHO Guideline Review Committee between 2007 and 2012. Teams of reviewers independently abstracted data from eligible guidelines and classified recommendations either into one of the five paradigms for appropriately-formulated discordant recommendations or into three additional categories in which discordant recommendations were inconsistent with GRADE guidance: 1) the evidence warranted moderate or high confidence (a misclassification of evidence) rather than low or very low confidence; 2) good practice statements; or 3) uncertainty in the estimates of effect would best lead to a conditional (weak) recommendation. RESULTS The 33 eligible guidelines included 160 discordant recommendations, of which 98 (61.3%) addressed drug interventions and 132 (82.5%) provided some rationale (though not entirely explicit at times) for the strong recommendation. Of 160 discordant recommendations, 25 (15.6%) were judged consistent with one of the five paradigms for appropriate recommendations; 33 (21%) were based on evidence warranting moderate or high confidence in the estimates of effect; 29 (18%) were good practice statements; and 73 (46%) warranted a conditional, rather than a strong recommendation. CONCLUSION WHO discordant recommendations are often inconsistent with GRADE guidance, possibly threatening the integrity of the process. Further training in GRADE methods for WHO guideline development group members may be necessary, along with further research on what motivates the formulation of such recommendations.

American Gastroenterological Association Institute Technical Review on the Management of Acute Diverticulitis

Division of Gastroenterology, Department of Medicine, University of Washington School of Medicine, Seattle, Washington; Division of Gastroenterology, Department of Medicine, University of North Carolina School of Medicine, Chapel Hill, North Carolina; Department of Internal Medicine, Faculty of Medicine, Pontificia Universidad Catolica de Chile, Santiago, Chile; and Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada

Learning from failure - rationale and design for a study about discontinuation of randomized trials (DISCO study)

BackgroundRandomized controlled trials (RCTs) may be discontinued because of apparent harm, benefit, or futility. Other RCTs are discontinued early because of insufficient recruitment. Trial discontinuation has ethical implications, because participants consent on the premise of contributing to new medical knowledge, Research Ethics Committees (RECs) spend considerable effort reviewing study protocols, and limited resources for conducting research are wasted. Currently, little is known regarding the frequency and characteristics of discontinued RCTs.Methods/DesignOur aims are, first, to determine the prevalence of RCT discontinuation for specific reasons; second, to determine whether the risk of RCT discontinuation for specific reasons differs between investigator- and industry-initiated RCTs; third, to identify risk factors for RCT discontinuation due to insufficient recruitment; fourth, to determine at what stage RCTs are discontinued; and fifth, to examine the publication history of discontinued RCTs.We are currently assembling a multicenter cohort of RCTs based on protocols approved between 2000 and 2002/3 by 6 RECs in Switzerland, Germany, and Canada. We are extracting data on RCT characteristics and planned recruitment for all included protocols. Completion and publication status is determined using information from correspondence between investigators and RECs, publications identified through literature searches, or by contacting the investigators. We will use multivariable regression models to identify risk factors for trial discontinuation due to insufficient recruitment. We aim to include over 1000 RCTs of which an anticipated 150 will have been discontinued due to insufficient recruitment.DiscussionOur study will provide insights into the prevalence and characteristics of RCTs that were discontinued. Effective recruitment strategies and the anticipation of problems are key issues in the planning and evaluation of trials by investigators, Clinical Trial Units, RECs and funding agencies. Identification and modification of barriers to successful study completion at an early stage could help to reduce the risk of trial discontinuation, save limited resources, and enable RCTs to better meet their ethical requirements.

Do clinicians understand the size of treatment effects? A randomized survey across 8 countries

Background: Meta-analyses of continuous outcomes typically provide enough information for decision-makers to evaluate the extent to which chance can explain apparent differences between interventions. The interpretation of the magnitude of these differences — from trivial to large — can, however, be challenging. We investigated clinicians’ understanding and perceptions of usefulness of 6 statistical formats for presenting continuous outcomes from meta-analyses (standardized mean difference, minimal important difference units, mean difference in natural units, ratio of means, relative risk and risk difference). Methods: We invited 610 staff and trainees in internal medicine and family medicine programs in 8 countries to participate. Paper-based, self-administered questionnaires presented summary estimates of hypothetical interventions versus placebo for chronic pain. The estimates showed either a small or a large effect for each of the 6 statistical formats for presenting continuous outcomes. Questions addressed participants’ understanding of the magnitude of treatment effects and their perception of the usefulness of the presentation format. We randomly assigned participants 1 of 4 versions of the questionnaire, each with a different effect size (large or small) and presentation order for the 6 formats (1 to 6, or 6 to 1). Results: Overall, 531 (87.0%) of the clinicians responded. Respondents best understood risk difference, followed by relative risk and ratio of means. Similarly, they perceived the dichotomous presentation of continuous outcomes (relative risk and risk difference) to be most useful. Presenting results as a standardized mean difference, the longest standing and most widely used approach, was poorly understood and perceived as least useful. Interpretation: None of the presentation formats were well understood or perceived as extremely useful. Clinicians best understood the dichotomous presentations of continuous outcomes and perceived them to be the most useful. Further initiatives to help clinicians better grasp the magnitude of the treatment effect are needed.

A number of factors explain why WHO guideline developers make strong recommendations inconsistent with GRADE guidance

OBJECTIVE Many strong recommendations issued by the World Health Organization (WHO) are based on low- or very low-quality (low certainty) evidence (discordant recommendations). Many such discordant recommendations are inconsistent with the Grading of Recommendations Assessment, Development and Evaluation (GRADE) guidance. We sought to understand why WHO makes discordant recommendations inconsistent with GRADE guidance. STUDY DESIGN AND SETTING We interviewed panel members involved in guidelines approved by WHO (2007-2012) that included discordant recommendations. Interviews, recorded and transcribed, focused on use of GRADE including the reasoning underlying, and factors contributing to, discordant recommendations. RESULTS Four themes emerged: strengths of GRADE, challenges and barriers to GRADE, strategies to improve GRADE application, and explanations for discordant recommendations. Reasons for discordant recommendations included skepticism about the value of making conditional recommendations; political considerations; high certainty in benefits (sometimes warranted, sometimes not) despite assessing evidence as low certainty; and concerns that conditional recommendations will be ignored. CONCLUSION WHO panelists make discordant recommendations inconsistent with GRADE guidance for reasons that include limitations in their understanding of GRADE. Ensuring optimal application of GRADE at WHO and elsewhere likely requires selecting panelists who have a commitment to GRADE principles, additional training of panelists, and formal processes to maximize adherence to GRADE principles.