Dataset Information

Non-Publication Is Common among Phase 1, Single-Center, Not Prospectively Registered, or Early Terminated Clinical Drug Trials.

ABSTRACT: The objective of this study was to investigate the occurrence and determinants of non-publication of clinical drug trials in the Netherlands.All clinical drug trials reviewed by the 28 Institutional Review Boards (IRBs) in the Netherlands in 2007 were followed-up from approval to publication. Candidate determinants were the sponsor, phase, applicant, centers, therapeutic effect expected, type of trial, approval status of the drug(s), drug type, participant category, oncology or other disease area, prospective registration, and early termination. The main outcome was publication as peer reviewed article. The percentage of trials that were published, crude and adjusted odds ratio (OR), and 95% confidence interval (CI) were used to quantify the associations between determinants and publication. In 2007, 622 clinical drug trials were reviewed by IRBs in the Netherlands. By the end of follow-up, 19 of these were rejected by the IRB, another 19 never started inclusion, and 10 were still running. Of the 574 trials remaining in the analysis, 334 (58%) were published as peer-reviewed article. The multivariable logistic regression model identified the following determinants with a robust, statistically significant association with publication: phase 2 (60% published; adjusted OR 2.6, 95% CI 1.1-5.9), phase 3 (73% published; adjusted OR 4.1, 95% CI 1.7-10.0), and trials not belonging to phase 1-4 (60% published; adjusted OR 3.2, 95% CI 1.5 to 6.5) compared to phase 1 trials (35% published); trials with a company or investigator as applicant (63% published) compared to trials with a Contract Research Organization (CRO) as applicant (50% published; adjusted OR 1.7; 95% CI 1.1-2.8); and multicenter trials also conducted in other EU countries (68% published; adjusted OR 2.2, 95% CI 1.1-4.4) or also outside the European Union (72% published; adjusted OR 2.0, 95% CI 1.0-4.0) compared to single-center trials (45% published). Trials that were not prospectively registered (48% published) had a lower likelihood of publication compared to prospectively registered trials (75% published; adjusted OR 0.5, 95% CI 0.3-0.8), as well as trials that were terminated early (33% published) compared to trials that were completed as planned (64% published; adjusted OR 0.2, 95% CI 0.1-0.3). The non-publication rate of clinical trials seems to have improved compared to previous inception cohorts, but is still far from optimal, in particular among phase 1, single-center, not prospectively registered, and early terminated trials.

SUBMITTER: van den Bogert CA

PROVIDER: S-EPMC5156378 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature

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Non-Publication Is Common among Phase 1, Single-Center, Not Prospectively Registered, or Early Terminated Clinical Drug Trials.

van den Bogert Cornelis A CA Souverein Patrick C PC Brekelmans Cecile T M CT Janssen Susan W J SW Koëter Gerard H GH Leufkens Hubert G M HG Bouter Lex M LM

PloS one 20161214 12

The objective of this study was to investigate the occurrence and determinants of non-publication of clinical drug trials in the Netherlands.All clinical drug trials reviewed by the 28 Institutional Review Boards (IRBs) in the Netherlands in 2007 were followed-up from approval to publication. Candidate determinants were the sponsor, phase, applicant, centers, therapeutic effect expected, type of trial, approval status of the drug(s), drug type, participant category, oncology or other disease are ...[more]

PMID: 27973571

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Project description:ImportanceThe published evidence in support of probiotic use is conflicting, which may be a result of selective publication of probiotic trials.ObjectivesTo compare the proportion of registered trials that evaluate pediatric probiotics vs those that evaluate antibiotics that are published and to identify study-related factors associated with publication status.Design, setting, and participantsThis cross-sectional study evaluated eligible trials registered in ClinicalTrials.gov, an online clinical trials registry, from July 1, 2005, to June 30, 2016. Eligible studies included participants younger than 18 years, evaluated a probiotic or 1 of the 5 most commonly prescribed antibiotics in children and adolescents, and randomized study participants. All searches were updated and finalized as of September 9, 2020.ExposuresProbiotic or antibiotic.Main outcomes and measuresThe primary outcome was study publication status. In addition, exposure status (probiotic vs antibiotic), trial result, and funding source were assessed for independent association with publication status. Whether study design elements, publication journal impact factor, and the interval from study completion to publication differed by exposure status were also evaluated.ResultsA total of 401 unique trials (265 probiotic and 136 antibiotic) met eligibility criteria. A greater proportion of antibiotic compared with probiotic studies were published (83 [61.0%] vs 119 [44.9%]; difference, 16.1% [95% CI, 5.8%-25.9%]). After adjustment for funding source, blinding, and purpose, studies evaluating an antibiotic were more likely to be published (odds ratio, 2.1 [95% CI, 1.3-3.4]). No other covariates included in the model were independently associated with publication status. Antibiotic trials, compared with probiotic trials, were more likely to have a therapeutic purpose (114 [83.8%] vs 117 [44.2%]; difference, 39.6% [95% CI, 31.1%-48.3%]) and to be multicenter (46 [33.8%] vs 46 [17.4%]; difference, 16.5% [95% CI, 7.5%-25.7%]). The median impact factor of the journals in which the studies were published was higher for the antibiotic trials (7.2 [IQR, 2.8-20.5] vs 3.0 [IQR, 2.3-4.2]; P < .001). The median number of days to publication did not differ between the probiotic and antibiotic trials (683 [IQR, 441-1036] vs 801 [IQR, 550-1183]; P = .24).Conclusions and relevanceThe findings of this cross-sectional study suggest that probiotic studies are less likely to be published than antibiotic trials. No other study characteristics were associated with publication status. This finding raises concerns regarding the results of meta-analyses of probiotic trials.

Project description:ImportancePublishing study protocols might reduce research waste because of unclear methods or incomplete reporting; on the other hand, there might be few additional benefits of publishing protocols for registered trials that are never completed or published. No study has investigated the proportion of published protocols associated with published results.ObjectiveTo estimate the proportion of published trial protocols for which there are not associated published results.Design, setting, and participantsThis cross-sectional study used stratified random sampling to identify registered clinical trials with protocols published between January 2011 and August 2022 and indexed in PubMed Central. Ongoing studies and those within 1 year of the primary completion date on ClinicalTrials.gov were excluded. Published results were sought from August 2022 to March 2023 by searching ClinicalTrials.gov, emailing authors, and using an automated tool, as well as through incidental discovery.Main outcomes and measuresThe primary outcome was a weighted estimate of the proportion of registered trials with published protocols that also had published main results. The proportion of trials with unpublished results was estimated using a weighted mean.ResultsFrom 1500 citations that were screened, 308 clinical trial protocols were included, and it was found that 87 trials had not published their main results. Most included trials were investigator-initiated evaluations of nonregulated products. When published, results appeared a mean (SD) of 3.4 (2.0) years after protocol publications. With the use of a weighted mean, an estimated 4754 (95% CI, 4296-5226) eligible clinical trial protocols were published and indexed in PubMed Central between 2011 and 2022. In the weighted analysis, 1708 of those protocols (36%; 95% CI, 31%-41%) were not associated with publication of main results. In a sensitivity analysis excluding protocols published after 2019, an estimated 25% (95% CI, 20%-30%) of 3670 (95% CI, 3310-4032) protocol publications were not associated with publication of main results.Conclusions and relevanceThis cross-sectional study of clinical trial protocols published on PubMed Central between 2011 and 2022 suggests that many protocols were not associated with subsequent publication of results. The overall benefits of publishing study protocols might outweigh the research waste caused by unnecessary protocol publications.

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Project description:Objective: This study aimed to analyze the characteristics and reasons of early discontinuation of obsessive-compulsive disorder (OCD) trials registered on ClinicalTrials.gov. Methods: OCD trials and relevant publications were searched on ClinicalTrials.gov and PubMed, respectively. The characteristics and details regarding the timely publication of trials were recorded. Cox regression analysis was used to explore factors associated with the early discontinuation of OCD trials. Results: The analysis included 298 OCD therapy trials. Most investigations recruited <100 patients and were more likely to involve adults. Of all OCD studies identified, 67.8% were randomized and 61.4% were blind (single- or double-blind). Universities and hospitals were recorded as the two primary locations in the majority of trials. A total of 155 trials (52%) were completed; however, only 29% of those were published. Of the published trials, >70% were published at least 1 year after completion. Behavioral therapy trials were the most common type of major treatment-aimed OCD trials (39%), followed by drug trials (35.1%) and device/procedure trials (24.7%). The univariate Cox regression analysis indicated that drug trials [hazard ratio (HR) = 2.56, 95% confidence interval (CI): 1.21-5.43], absence of collaborators (HR = 3.87, 95% CI: 1.62-9.26), and sponsorship by industry (HR = 3.97, 95% CI: 1.49-10.53) were risk factors for early discontinuation of OCD trials. Further multivariate Cox regression showed that drug trials (HR = 3.93, 95% CI: 1.71-9.08) and absence of collaborators (HR = 5.17, 95% CI: 1.97-13.54) were independent risk factors for early trial discontinuation of OCD trials. The sensitivity analysis confirmed these results. Non-drug trials (OR = 3.32, 95% CI: 1.21-9.11), absence of collaborators (OR = 3.25, 95% CI: 1.10-9.60), and non-blinded trials (OR = 5.23, 95% CI: 1.05-26.2) were independent risk factors for unreported results in registry. Conclusion: The diagnosis and prevention of OCD are rarely investigated in trials. Underreporting and delayed reporting remain major problems. The type of intervention and participation of collaborators are associated with early discontinuation of OCD trials.

Dataset Information

Non-Publication Is Common among Phase 1, Single-Center, Not Prospectively Registered, or Early Terminated Clinical Drug Trials.

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Non-Publication Is Common among Phase 1, Single-Center, Not Prospectively Registered, or Early Terminated Clinical Drug Trials.

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