Timing and Completeness of Trial Results Posted at ClinicalTrials.gov and Published in Journals

Riveros, Carolina; Dechartres, Agnès; Perrodeau, Élodie; Haneef, Romana; Boutron, Isabelle; Ravaud, Philippe

doi:10.1371/journal.pmed.1001566

Cited by 218 publications

(203 citation statements)

References 33 publications

(28 reference statements)

Supporting

Mentioning

190

Contrasting

Unclassified

Order By: Relevance

“…However, we are aware of the fact that this may be biased by the respective authors that tend to underestimate or undervalue negative results, for instance in comparison to registered trial reports. 81,82 We found that 14 of the 27 studies reported negative outcome on global symptoms, however individual symptoms (bloating 67,77 and satiety 69 ) were occasionally reported as being responsive to treatment. Quality of life (QoL) improved in one study but symptomatic improvement was not different from placebo.…”

Section: Global Outcomementioning

confidence: 87%

Probiotic Therapy of the Irritable Bowel Syndrome: Why Is the Evidence Still Poor and What Can Be Done About It?

Mazurak

Broelz²,

Storr

et al. 2015

J Neurogastroenterol Motil

View full text Add to dashboard Cite

Background/AimsDespite numerous randomized clinical trials and meta-analyses, there is no increased evidence for the efficacy of probiotics in the treatment of irritable bowel syndrome (IBS). We review this evidence, identify and analyse the reasons for this lack of evidence and propose methodological improvements for future studies. MethodsBased on a literature search, we identified 56 papers that matched the purpose of our analyses. Twenty-seven studies used multi-species bacterial preparations and 29 used single-strain probiotics. They were analysed regarding patients included, treatment duration, probiotic dosage, and outcome measures. ResultsTrials in both groups suffered from heterogeneity with respect to probiotic concentration, duration of treatment, and other methodological issues (crossover design and underpowered studies). This heterogeneity did not allow the application of a meta-analytic approach and a systematic review was therefore performed instead. Multi-strain preparations combined 2 to 8 different bacterial subspecies, mostly lactobacilli or bifidobacteria, and used variable lengths of treatments. Overall, more than 50% of trials presented negative outcomes. The majority of the single-strain probiotic trials employing lactobacilli or Saccharomyces were negative, whereas trials employing bifidobacteria showed positive results. ConclusionsThe heterogeneity of the studies of probiotics in IBS questions the value of meta-analyses. The use of different bacterial strains and different mixtures of these strains, as well as different dosages, are the main contributors to this heterogeneity. Current data provides limited evidence for the efficacy of a small number of single-strain probiotics in IBS (mostly bifidobacteria) and

show abstract

Section: Global Outcomementioning

confidence: 87%

Probiotic Therapy of the Irritable Bowel Syndrome: Why Is the Evidence Still Poor and What Can Be Done About It?

Mazurak

Broelz²,

Storr

et al. 2015

J Neurogastroenterol Motil

View full text Add to dashboard Cite

show abstract

“…12 For such analyses, the publication date was the date reported after the wording "results first received" for the unpublished trials; the earlier of either the publication date or the date that the results were made available on ClinicalTrials.gov for published trials.…”

Section: Statistical Analysesmentioning

confidence: 99%

“…Posting results on registry websites does not negate the importance of peer reviewed publication, 43 44 but our data show that ClinicalTrials.gov can serve a useful role in enhancing the completeness of available information. 12 Some considerations on the search for published reports are needed. A previous survey 20 found that a substantial proportion of randomized controlled trials (40-45%) is still being published without the reporting of a trial registration code, thereby weakening the ability of the researchers to identify multiple publications of the same trial, cross check the published report with the original design, and investigate selective reporting.…”

Section: Policy Implicationsmentioning

confidence: 99%

Non-publication and delayed publication of randomized trials on vaccines: a survey

Manzoli

Flacco

D’Addario

et al. 2014

European Journal of Public Health

View full text Add to dashboard Cite

Objective To evaluate the extent of non-publication or delayed publication of registered randomized trials on vaccines, and to investigate potential determinants of delay to publication. Design Survey.Data sources Trials registry websites, Scopus, PubMed, Google. Main outcome measures Publication status of trial results and time from completion to publication in peer reviewed journals. Study selectionData synthesis Cox proportional hazards regression was used to evaluate potential predictors of publication delay. ResultsWe analysed 384 trials (85% sponsored by industry). Of 355 trials (404 758 participants) that were completed, 176 (n=151 379) had been published in peer reviewed journals. Another 42 trials (total sample 62 765) remained unpublished but reported results in ClinicalTrials.gov. The proportion of trials published 12, 24, 36, and 48 months after completion was 12%, 29%, 53%, and 73%, respectively. Including results posted in ClinicalTrials.gov, 48 months after study completion results were available for 82% of the trials and 90% of the participants. Delay to publication between non-industry and industry sponsored trials did not differ, but non-industry sponsored trials were 4.42-fold (P=0.008) more likely to report negative or mixed findings. Negative results were reported by only 2% of the published trials.Conclusions Most vaccine trials are published eventually or the results posted in ClinicalTrials.gov, but delays to publication of several years are common. Actions should focus on the timely dissemination of data from vaccine trials to the public.

show abstract

“…Alarge percentage ofclinical trial resultsremainunpublishedinthe biomedical literature long after their data reach maturity [1][2][3][4][5][6]. In few areas of medicine is the timely dissemination of clinical trial results more crucial than in oncology, because this knowledge is used to optimize dynamic treatment decisions, often involving the ongoing, off-label use of drugs already approved [7].…”

Section: Introductionmentioning

confidence: 99%

Assessing the Eventual Publication of Clinical Trial Abstracts Submitted to a Large Annual Oncology Meeting

et al. 2016

View full text Add to dashboard Cite

Background. Despite the ethical imperative to publish clinical trials when human subjects are involved, such data frequently remain unpublished. The objectives were to tabulate the rate and ascertain factors associated with eventual publication of clinical trial results reported as abstracts in the Proceedings of the American Society of Clinical Oncology (American Society of Clinical Oncology). Materials and Methods. Abstracts describing clinical trials for patients with breast, lung, colorectal, ovarian, and prostate cancer from 2009 to 2011 were identified by using a comprehensive online database (http://meetinglibrary.asco. org/abstracts). Abstracts included reported results of a treatment or intervention assessed in a discrete, prospective clinical trial. Publication status at 426 years was determined by using a standardized search of PubMed. Primary outcomes were the rate of publication for abstracts of randomized and nonrandomized clinical trials. Secondary outcomes included factors influencing the publication of results. Results. A total of 1,075 abstracts describing 378 randomized and 697 nonrandomized clinical trials were evaluated. Across all years, 75% of randomized and 54% of nonrandomized trials were published, with an overall publication rate of 61%. Sample

show abstract

Timing and Completeness of Trial Results Posted at ClinicalTrials.gov and Published in Journals

Abstract: Agnes Dechartres and colleagues searched ClinicalTrials.gov for completed drug RCTs with results reported and then searched for corresponding studies in PubMed to evaluate timeliness and completeness of reporting. Please see later in the article for the Editors' Summary

Cited by 218 publications

References 33 publications

Probiotic Therapy of the Irritable Bowel Syndrome: Why Is the Evidence Still Poor and What Can Be Done About It?

Probiotic Therapy of the Irritable Bowel Syndrome: Why Is the Evidence Still Poor and What Can Be Done About It?

Non-publication and delayed publication of randomized trials on vaccines: a survey

Assessing the Eventual Publication of Clinical Trial Abstracts Submitted to a Large Annual Oncology Meeting

Contact Info

Product

Resources

About