Results and outcome reporting In ClinicalTrials.gov, what makes it happen?

Research integrity and the law that never was

Evidence-based medicine is arguably among the most important innovations of the modern era, but publication bias and inadequate research transparency are serious issues affecting the very foundation of evidence-based practice. Despite this truth, these crucial issues have gone largely unaddressed or inadequately addressed for a distressingly long period of time. Regulatory efforts have thus far proven insufficient in eliminating these issues. Fortunately, the last 5 years in particular have seen developments that one hopes will contribute to the eradication of these issues and a future where we can look back on these issues as a sordid story of our past. However, much like the purported fixes of the past, time will be the final arbiter of the efficacy of remedial measures currently underway. This article chronicles the history of these issues, failed attempts to fix these issues, and what can be and is being done with the hope of bringing about true resolution.

Randomized controlled trials of rheumatoid arthritis registered at ClinicalTrials.gov: what gets published and when

OBJECTIVE

To examine characteristics associated with the publication and timeliness of publication of randomized controlled trials (RCTs) of treatment of rheumatoid arthritis (RA).

METHODS

RA RCTs (phases II-IV) registered at ClinicalTrials.gov and completed by December 31, 2009 were identified. A standardized strategy was used to determine publication status and outcome assessment. The association of RCT characteristics recorded at ClinicalTrials.gov and study outcome with publication and time to publication were assessed.

RESULTS

A search conducted at least 30 months after trial completion revealed that among 143 eligible RCTs, 95 (64.4%) were published. The 48 unpublished RCTs had enrolled >10,000 patients. Efficacy outcomes could be ascertained for 127 of the RCTs. RCT publication was associated with positive outcome, with an adjusted odds ratio [OR] of 4.3 (95% confidence interval [95% CI] 1.8-10.2) (P = 0.001), and marginally with RCT registration before completion (adjusted OR 0.4 [95% CI 0.1-1.0], P = 0.06). The estimated median time to publication was 38 months. Positive outcome was associated with earlier publication (adjusted hazard ratio 1.9 [95% CI 1.2-2.9], P = 0.006). RCTs completed in 2006-2007 or 2008-2009 were likely to be published sooner than RCTs completed in or before 2005. Sensitivity analyses to assess the impact of 16 RCTs with unknown outcome did not alter these findings, except in the highly implausible scenario of all such trials being positive.

CONCLUSION

Positive study outcome was associated with publication and timeliness of publication despite registration in a publicly available registry. A substantial minority of RA RCTs remained unpublished. Efforts to improve transparency in reporting of clinical trials need to continue.

A machine learning approach to identify clinical trials involving nanodrugs and nanodevices from ClinicalTrials.gov

BACKGROUND

Clinical Trials (CTs) are essential for bridging the gap between experimental research on new drugs and their clinical application. Just like CTs for traditional drugs and biologics have helped accelerate the translation of biomedical findings into medical practice, CTs for nanodrugs and nanodevices could advance novel nanomaterials as agents for diagnosis and therapy. Although there is publicly available information about nanomedicine-related CTs, the online archiving of this information is carried out without adhering to criteria that discriminate between studies involving nanomaterials or nanotechnology-based processes (nano), and CTs that do not involve nanotechnology (non-nano). Finding out whether nanodrugs and nanodevices were involved in a study from CT summaries alone is a challenging task. At the time of writing, CTs archived in the well-known online registry ClinicalTrials.gov are not easily told apart as to whether they are nano or non-nano CTs-even when performed by domain experts, due to the lack of both a common definition for nanotechnology and of standards for reporting nanomedical experiments and results.

METHODS

We propose a supervised learning approach for classifying CT summaries from ClinicalTrials.gov according to whether they fall into the nano or the non-nano categories. Our method involves several stages: i) extraction and manual annotation of CTs as nano vs. non-nano, ii) pre-processing and automatic classification, and iii) performance evaluation using several state-of-the-art classifiers under different transformations of the original dataset.

RESULTS AND CONCLUSIONS

The performance of the best automated classifier closely matches that of experts (AUC over 0.95), suggesting that it is feasible to automatically detect the presence of nanotechnology products in CT summaries with a high degree of accuracy. This can significantly speed up the process of finding whether reports on ClinicalTrials.gov might be relevant to a particular nanoparticle or nanodevice, which is essential to discover any precedents for nanotoxicity events or advantages for targeted drug therapy.

How transparent are migraine clinical trials? Repository of Registered Migraine Trials (RReMiT)

Transparency in research requires public access to unbiased information prior to trial initiation and openly available results upon study completion. The Repository of Registered Migraine Trials is a global snapshot of registered migraine clinical trials and scorecard of results availability via the peer-reviewed literature, registry databases, and gray literature. The 295 unique clinical trials identified employed 447 investigational agents, with 30% of 154 acute migraine trials and 11% of 141 migraine prophylaxis trials testing combinations of agents. The most frequently studied categories in acute migraine trials were triptans, nonsteroidal anti-inflammatory drugs, antiemetics, calcitonin gene-related peptide antagonists, and acetaminophen. Migraine prophylaxis trials frequently studied anticonvulsants, β-blockers, complementary/alternative therapies, antidepressants, and botulinum toxin. Overall, 237 trials were eligible for a results search. Of 163 trials completed at least 12 months earlier, 57% had peer-reviewed literature results, and registries/gray literature added another 13%. Using logistic regression analysis, studies with a sample size below the median of 141 subjects were significantly less likely to have results, but the dominant factor associated with availability of results was time since study completion. In unadjusted models, trials registered on ClinicalTrials.gov and trials with industry primary sponsorship were significantly more likely to have results. Recently completed trials rarely have publicly available results; 2 years after completion, the peer-reviewed literature contains results for fewer than 60% of completed migraine trials. To avoid bias, evidence-based therapy algorithms should consider factors affecting results availability. As negative trials are less likely to be published, special caution should be exercised before recommending a therapy with a high proportion of missing trial results.

Registration and design alterations of clinical trials in critical care: a cross-sectional observational study

PURPOSE

In 2005 the International Committee of Medical Journal Editors issued a requirement that all randomized controlled trials (RCTs) be registered primarily to prevent selective reporting (publication bias). However, registries allow for alterations in study protocol. Changes occurring before (or after) study completion could invalidate the original study intent, leading to publication of misleading conclusions. In RCTs involving critically ill patients, these concerns may be particularly acute because mortality is high and conditions investigated are usually syndromes rather than specific diseases. This study was conducted to estimate the registration rate of RCTs in critical care; and, among registered RCTs, to determine timing of registration and whether sample size or primary outcome were altered.

METHODS

We searched the MEDLINE database for RCTs that began after or continued through July 2005. We determined whether each trial had been registered and, for registered trials, compared registry data to data in the published manuscript.

RESULTS

Approximately two-thirds (66%) of trials were registered. Of these, 66% of registrations occurred after enrolment had commenced. Overall, 6% (5/90) of trials appropriately registered a sample size which was unchanged from the interval between registration and publication, and only 12% (11/90) reported primary outcomes that were both appropriately registered and unchanged.

CONCLUSIONS

Non-registration, or registration after trial initiation, are common in RCTs of critically ill patients. Among registered trials important protocol changes are often made between trial commencement and publication. This study identifies and quantifies the extent of this serious-but correctable-problem for RCTs in critically ill patients.

RReACT goes global: perils and pitfalls of constructing a global open-access database of registered analgesic clinical trials and trial results

Eliminating publication bias requires ensuring public awareness of studies and access to results. Clinical trial registries provide basic trial information, but access to unbiased trial results is inadequate. Nearly all studies of trial registration and results reporting have been limited to the ClinicalTrials.gov registry. We analyzed trial registration, registry functionality, cross-registry harmonization, and results reporting on all 15 primary registries in the World Health Organization International Clinical Trials Registry Platform (ICTRP) for postherpetic neuralgia, painful diabetic neuropathy, and fibromyalgia. A total of 447 unique trials were identified, with 86 trials listed on more than one registry. A comprehensive search algorithm was used to find trial results in the peer-reviewed literature and the grey literature. Creating a global database of registered trials and trial results proved surprisingly difficult for several reasons: (1) ICTRP does not reliably identify trials listed on multiple registries, manual searches are necessary; (2) Searching ICTRP yields different results than searching individual registries; (3) Outcome measure descriptions for multiply registered trials vary between registries; (4) Registry-publication pairings are often inaccurate or incomplete; (5) Grey literature results are not permanent. Overall, only 46% of all trials had results available. Trials registered on ClinicalTrials.gov were significantly more likely to have results (52% vs. 18%, P<0.001), partly due to the ability to post results directly to the registry. In addition to the simple remedy of including trial registration numbers on all meeting abstracts and peer-reviewed papers, specific strategies are offered to facilitate identifying multiply registered studies and ensuring accurate pairing of results and publications.

Linking ClinicalTrials.gov and PubMed to track results of interventional human clinical trials

Objective

In an effort to understand how results of human clinical trials are made public, we analyze a large set of clinical trials registered at ClinicalTrials.gov, the world’s largest clinical trial registry.

Materials and Methods

We considered two trial result artifacts: (1) existence of a trial result journal article that is formally linked to a registered trial or (2) the deposition of a trial’s basic summary results within the registry.

Results

The study sample consisted of 8907 completed, interventional, phase 2-or-higher clinical trials that were completed in 2006-2009. The majority of trials (72.2%) had no structured trial-article link present. Atotal of 2367 trials (26.6%) deposited basic summary results within the registry. Ofthose, 969 trials (10.9%) were classified as trials with extended results and 1398 trials (15.7%) were classified as trials with only required basic results. The majority of the trials (54.8%) had no evidence of results, based on either linked result articles or basic summary results (silent trials), while a minimal number (9.2%) report results through both registry deposition and publication.

Discussion

Our study analyzes the body of linked knowledge around clinical trials (which we refer to as the “trialome”). Our results show that most trials do not report results and, for those that do, there is minimal overlap in the types of reporting. We identify several mechanisms by which the linkages between trials and their published results can be increased.

Conclusion

Our study shows that even when combining publications and registry results, and despite availability of several information channels, trial sponsors do not sufficiently meet the mandate to inform the public either via a linked result publication or basic results submission.