Dataset Information

Funding source and primary outcome changes in clinical trials registered on ClinicalTrials.gov are associated with the reporting of a statistically significant primary outcome: a cross-sectional study.

ABSTRACT:

Background

We and others have shown a significant proportion of interventional trials registered on ClinicalTrials.gov have their primary outcomes altered after the listed study start and completion dates. The objectives of this study were to investigate whether changes made to primary outcomes are associated with the likelihood of reporting a statistically significant primary outcome on ClinicalTrials.gov.

Methods

A cross-sectional analysis of all interventional clinical trials registered on ClinicalTrials.gov as of 20 November 2014 was performed. The main outcome was any change made to the initially listed primary outcome and the time of the change in relation to the trial start and end date.

Findings

13,238 completed interventional trials were registered with ClinicalTrials.gov that also had study results posted on the website. 2555 (19.3%) had one or more statistically significant primary outcomes. Statistical analysis showed that registration year, funding source and primary outcome change after trial completion were associated with reporting a statistically significant primary outcome .

Conclusions

Funding source and primary outcome change after trial completion are associated with a statistically significant primary outcome report on clinicaltrials.gov.

SUBMITTER: Ramagopalan SV

PROVIDER: S-EPMC4431380 | biostudies-literature | 2015

REPOSITORIES: biostudies-literature

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Publications

Funding source and primary outcome changes in clinical trials registered on ClinicalTrials.gov are associated with the reporting of a statistically significant primary outcome: a cross-sectional study.

Ramagopalan Sreeram V SV Skingsley Andrew P AP Handunnetthi Lahiru L Magnus Daniel D Klingel Michelle M Pakpoor Julia J Goldacre Ben B

F1000Research 20150326

<h4>Background</h4>We and others have shown a significant proportion of interventional trials registered on ClinicalTrials.gov have their primary outcomes altered after the listed study start and completion dates. The objectives of this study were to investigate whether changes made to primary outcomes are associated with the likelihood of reporting a statistically significant primary outcome on ClinicalTrials.gov.<h4>Methods</h4>A cross-sectional analysis of all interventional clinical trials r ...[more]

PMID: 26069729

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Project description:BackgroundSpin in the reporting of randomized controlled trials, where authors report research in a way that potentially misrepresents results and mislead readers, has been demonstrated in the broader medical literature. We investigated spin in wound care trials with (a) no statistically significant result for the primary outcome and (b) no clearly specified primary outcome.MethodsWe searched the Cochrane Wounds Group Specialised Register of Trials for randomized controlled trials (RCTs). Eligible studies were: Parallel-group RCTs of interventions for foot, leg or pressure ulcers published in 2004 to 2009 (inclusive) with either a clearly identified primary outcome for which there was a statistically non-significant result (Cohort A) or studies that had no clear primary outcome (Cohort B).We extracted general study details. For both Cohorts A and B we then assessed for the presence of spin. For Cohort A we used a pre-defined process to assess reports for spin. For Cohort B we aimed to assess spin by recording the number of positive treatment effect claims made. We also compared the number of statistically significant and non-significant results reported in the main text and the abstract looking specifically for spin in the form of selective outcome reporting.ResultsOf the 71 eligible studies, 28 were eligible for Cohort A; of these, 71% (20/28) contained spin. Cohort B contained 43 studies; of these, 86% (37/43) had abstracts that claimed a favorable treatment claim. Whilst 74% (32/43) of main text results in Cohort B included at least one statistically non-significant result, this was not reflected in the abstract where only 28% contained (12/43) at least one statistically non-significant result.ConclusionsSpin is a frequent phenomenon in reports of RCTs of wound treatments. Studies without statistically significant results for the primary outcome used spin in 71% of cases. Furthermore, 33% (43/132) of reports of wound RCTs did not specify a primary outcome and there was evidence of spin and selective outcome reporting in the abstracts of these. Readers should be wary of only reading the abstracts of reports of RCTs of wound treatments since they are frequently misleading regarding treatment effects.

Project description:Aim: To evaluate the completeness of the description of nonsurgical periodontal therapy interventions in clinical trials registered in ClinicalTrials.gov and correspondence of registered information for trial participants and outcome measures with published articles. Materials & methods: We retrieved data from ClinicalTrials.gov and corresponding publications. The completeness of intervention reporting was assessed using the Template for Intervention Description and Replication (TIDieR) checklist for oral hygiene instructions (OHI), professional mechanical plaque removal (PMPR), and subgingival instrumentation, antiseptics and antibiotics. The completeness of registration of trial protocol information was assessed according to the WHO Trial Registration DataSet for participant information (enrollment, sample size calculation, age, gender, condition) and primary/secondary outcome measures. Results: 79 included trials involved OHI (n = 38 trials, 48.1%), PMPR (n = 19, 24.1%), antiseptics (n = 11, 12.7%), or antibiotics (n = 11, 12.7%). There was a great variety in the terms used to describe these interventions. Most of the analyzed trials (93.7%) were completed and did not provide any data on study phase (74.7%). The description of intervention in the registry in ClinicalTrials.gov was inadequate for all analyzed interventions, with description inconsistencies in matching publications. There were also discrepancies in registered and published outcomes: for 39 trials with published results, 18 had different registered and reported primary outcomes, and 29 different registered and reported secondary outcomes. Conclusion: The completeness of the description of nonsurgical therapy of periodontitis in clinical trials is unsatisfactory, reducing the quality of translation of the new evidence and procedures into clinical practice. Significant discrepancy in registered and reported trial outcomes calls into question the validity of reported results and relevance for practice.

Project description:ImportanceFor findings from clinical trials to be actionable, outcomes measured in trials must be fully defined and, when appropriate, defined consistently across trials. Otherwise, it is difficult to compare findings between trials, combine results in meta-analyses, or leverage findings collectively to inform health care decision-making.ObjectiveTo identify and characterize outcomes specified in ClinicalTrials.gov records for publicly funded clinical trials for 3 high-burden, high-prevalence eye conditions.Design, setting, and participantsClinicalTrials.gov, a registry of publicly and privately supported clinical studies, was searched on January 31, 2019, for records of clinical trials for age-related macular degeneration (AMD), dry eye, or refractive error. The search was limited to trials funded by the National Eye Institute but did not impose a date restriction. Five elements of a well-specified outcome were extracted from each outcome stated in each record, including the domain, method of measurement, metric, method of aggregation, and time points.Main outcomes and measuresNumber of outcome domains specified for trials for AMD, dry eye, and refractive error and the number of trial records specifying each unique domain.ResultsA total of 49 unique outcome domains specified across 39 records of trials were identified. The median (interquartile range) number of records specifying each unique outcome domain was 1 (1-3), 1.5 (1-2), and 1 (1-1) for AMD, dry eye, and refractive error, respectively. Even when the same domains were registered across multiple trials, the time point, specific metric, and method of aggregation were specified in multiple ways.Conclusions and relevanceThere were too many outcomes with too little overlap in the sample of trials that were examined. Differences in how outcomes are measured across trials make it difficult to compare results, even for well-established domains, such as visual acuity. To reduce this waste in eye and vision research, the time is ripe for agreeing on what outcomes to measure.

Project description:BackgroundThe $1.1 billion investment in comparative effectiveness research will reshape the evidence-base supporting decisions about treatment effectiveness, safety, and cost. Defining the current prevalence and characteristics of comparative effectiveness (CE) research will enable future assessments of the impact of this program.MethodsWe conducted an observational study of clinical trials addressing priority research topics defined by the Institute of Medicine and conducted in the US between 2007 and 2010. Trials were identified in ClinicalTrials.gov. Main outcome measures were the prevalence of comparative effectiveness research, nature of comparators selected, funding sources, and impact of these factors on results.Results231 (22.3%; 95% CI 19.8%-24.9%) studies were CE studies and 804 (77.7%; 95% CI, 75.1%-80.2%) were non-CE studies, with 379 (36.6%; 95% CI, 33.7%-39.6%) employing a placebo control and 425 (41.1%; 95% CI, 38.1%-44.1%) no control. The most common treatments examined in CE studies were drug interventions (37.2%), behavioral interventions (28.6%), and procedures (15.6%). Study findings were favorable for the experimental treatment in 34.8% of CE studies and greater than twice as many (78.6%) non-CE studies (P<0.001). CE studies were more likely to receive government funding (P?=?0.003) and less likely to receive industry funding (P?=?0.01), with 71.8% of CE studies primarily funded by a noncommercial source. The types of interventions studied differed based on funding source, with 95.4% of industry trials studying a drug or device. In addition, industry-funded CE studies were associated with the fewest pediatric subjects (P<0.001), the largest anticipated sample size (P<0.001), and the shortest study duration (P<0.001).ConclusionsIn this sample of studies examining high priority areas for CE research, less than a quarter are CE studies and the majority is supported by government and nonprofits. The low prevalence of CE research exists across CE studies with a broad array of interventions and characteristics.

Dataset Information

Funding source and primary outcome changes in clinical trials registered on ClinicalTrials.gov are associated with the reporting of a statistically significant primary outcome: a cross-sectional study.

Background

Methods

Findings

Conclusions

Publications

Funding source and primary outcome changes in clinical trials registered on ClinicalTrials.gov are associated with the reporting of a statistically significant primary outcome: a cross-sectional study.

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