Comparison of reporting phase III randomized controlled trials of antibiotic treatment for common bacterial infections in ClinicalTrials.gov and matched publications

Availability of results of clinical trials registered on EU Clinical Trials Register: cross sectional audit study

Objective

To identify the availability of results for trials registered on the European Union Clinical Trials Register (EUCTR) compared with other dissemination routes to understand its value as a results repository.

Design

Cross sectional audit study.

Setting

EUCTR protocols and results sections, data extracted 1-3 December 2020.

Population

Random sample of 500 trials registered on EUCTR with a completion date of more than two years from the beginning of searches (ie, 1 December 2018).

Main outcome measures

Proportion of trials with results across the examined dissemination routes (EUCTR, ClinicalTrials.gov, ISRCTN registry, and journal publications), and for each dissemination route individually. Prespecified secondary outcomes were number and proportion of unique results, and the timing of results, for each dissemination route.

Results

In the sample of 500 trials, availability of results on EUCTR (53.2%, 95% confidence interval 48.8% to 57.6%) was similar to the peer reviewed literature (58.6%, 54.3% to 62.9%) and exceeded the proportion of results available on other registries with matched records. Among the 383 trials with any results, 55 (14.4%, 10.9% to 17.9%) were only available on EUCTR. Also, after the launch of the EUCTR results database, median time to results was fastest on EUCTR (1142 days, 95% confidence interval 812 to 1492), comparable with journal publications (1226 days, 1074 to 1551), and exceeding ClinicalTrials.gov (3321 days, 1653 to undefined). For 117 trials (23.4%, 19.7% to 27.1%), however, results were published elsewhere but not submitted to the EUCTR registry, and no results were located in any dissemination route for 117 trials (23.4%, 19.7% to 27.1).

Conclusions

EUCTR should be considered in results searches for systematic reviews and can help researchers and the public to access the results of clinical trials, unavailable elsewhere, in a timely way. Reporting requirements, such as the EU's, can help in avoiding research waste by ensuring results are reported. The registry's true value, however, is unrealised because of inadequate compliance with EU guidelines, and problems with data quality that complicate the routine use of the registry. As the EU transitions to a new registry, continuing to emphasise the importance of EUCTR and the provision of timely and complete data is critical. For the future, EUCTR will still hold important information from the past two decades of clinical research in Europe. With increased efforts from sponsors and regulators, the registry can continue to grow as a source of results of clinical trials, many of which might be unavailable from other dissemination routes.

Estimating the prevalence of discrepancies between study registrations and publications: a systematic review and meta-analyses

OBJECTIVES

Prospectively registering study plans in a permanent time-stamped and publicly accessible document is becoming more common across disciplines and aims to reduce risk of bias and make risk of bias transparent. Selective reporting persists, however, when researchers deviate from their registered plans without disclosure. This systematic review aimed to estimate the prevalence of undisclosed discrepancies between prospectively registered study plans and their associated publication. We further aimed to identify the research disciplines where these discrepancies have been observed, whether interventions to reduce discrepancies have been conducted, and gaps in the literature.

DESIGN

Systematic review and meta-analyses.

DATA SOURCES

Scopus and Web of Knowledge, published up to 15 December 2019.

ELIGIBILITY CRITERIA

Articles that included quantitative data about discrepancies between registrations or study protocols and their associated publications.

DATA EXTRACTION AND SYNTHESIS

Each included article was independently coded by two reviewers using a coding form designed for this review (osf.io/728ys). We used random-effects meta-analyses to synthesise the results.

RESULTS

We reviewed k=89 articles, which included k=70 that reported on primary outcome discrepancies from n=6314 studies and, k=22 that reported on secondary outcome discrepancies from n=1436 studies. Meta-analyses indicated that between 29% and 37% (95% CI) of studies contained at least one primary outcome discrepancy and between 50% and 75% (95% CI) contained at least one secondary outcome discrepancy. Almost all articles assessed clinical literature, and there was considerable heterogeneity. We identified only one article that attempted to correct discrepancies.

CONCLUSIONS

Many articles did not include information on whether discrepancies were disclosed, which version of a registration they compared publications to and whether the registration was prospective. Thus, our estimates represent discrepancies broadly, rather than our target of undisclosed discrepancies between prospectively registered study plans and their associated publications. Discrepancies are common and reduce the trustworthiness of medical research. Interventions to reduce discrepancies could prove valuable.

REGISTRATION

osf.io/ktmdg. Protocol amendments are listed in online supplemental material A.

Selective Reporting of Outcomes in Tinnitus Trials: Comparison of Trial Registries With Corresponding Publications

Objectives: We aimed to study the prevalence of selective reporting of primary and secondary outcomes in tinnitus trials and to examine if selective reporting of outcome measures is influenced by the nature and direction of its results.

Background: Selective reporting of outcome measures has been reported in several biomedical fields and can influence the clinical usefulness and implementation of outcomes of clinical trials. It is reported as one of the obstacles in finding an effective intervention for tinnitus.

Methods: ClinicalTrials.gov (CT.gov) was used to identify all registered interventional tinnitus trials up to December 2015. A standardized search was used to find corresponding publications up to March 2018. The prespecified outcomes in CT.gov were compared with the outcomes reported in corresponding publication(s). The effects of the (lack of) statistical significance of trial results and the effects of funding source on record adherence were evaluated. Changes in registration elements were assessed with the Archive site of CT.gov.

Results: We found corresponding publications for 60 (64.5%) of 93 eligible tinnitus trials registered in CT.gov. Of all the publications, five (7.5%) fully reported outcome measures entirely in line with the prespecified outcome measures. Discrepancies between the prespecified and reported outcomes were found in a total of 51 (76.1%) of the studies for primary outcomes, whereas 62 (92.5%) of the studies had discrepancies in secondary outcomes. In secondary outcomes, statistical significance of trial results influenced CT.gov record adherence. In addition, there was a statistically significant difference in the rate of discrepancy in industry-funded [n = 98 (87.5%) discrepant outcomes] and non-industry funded trials [n = 172 (74.5%) discrepant outcomes] (p = 0.01). Finally, 15 (25.9%) trialists made modifications in registered outcome measures during or after the trial period.

Conclusion: Tinnitus trials suffer from substantial outcome reporting bias. Awareness of its presence must be raised to limit the obstacles of finding an effective intervention for tinnitus.

Public availability of results of ClinicalTrials.gov-registered expanded access studies

AIMS

Expanded access is the use of investigational treatments outside of clinical trials. Results of expanded access studies provide insights into how investigational treatments work in real-world settings. The objective of this study was to evaluate public availability of results of expanded access studies.

METHODS

Eligible expanded access studies were identified in ClinicalTrials.gov (CT.gov). Publications matching records of individual studies were searched for in Medline and Embase. In addition, we assessed whether results of the included studies were publicly available from other sources including CT.gov, sponsor web sites and conference proceedings.

RESULTS

After median time of 49.5 (interquartile range, 36.7-64.7) months from study completion, the results of 69 out of the 152 included studies (45.39%) were publicly available, either as a journal publication (53 studies; 34.87%) or from other source (16 studies; 10.52%). The percentage of studies whose results were available as a journal publication after 12, 24, 36 and 48 months from study completion was 13.2, 21.1, 33.1 and 35.7%, respectively. The percentage of studies whose results were publicly available from any source (including journal publications) at 12, 24, 36 and 48 months were 19.1, 29.6, 43.2 and 47.5%, respectively.

CONCLUSION

Results of a considerable proportion of expanded access studies are not publicly available. In view of the growing importance of real-world data, sponsors and principal investigators of those studies should always consider making their findings public.

Assessment of frequency and reporting of design changes among clinical drug trials published in influential medical journals

BACKGROUND

Modifications of primary outcome measures after trial initiation can undermine their scientific validity. We aimed to quantify these changes and to characterize potential predictors in clinical drug trials published in high impact factor general medicine journals.

METHODS

The study cohort included all prospective, adult drug clinical trials published in the New England Journal of Medicine, JAMA and Lancet between June 2017 and May 2018. The matching ClinicalTrials.gov entries effective at trial initiation were compared with those effective on July 2018, thereby identifying amendments to primary outcome definitions and assessment timeframes and the planned sample size (defined as >10% change). The primary publications were reviewed for reporting of these amendments. Associations between identified changes and trial characteristics were explored using logistic regression.

RESULTS

Of the 147 included trials, modifications to primary outcome measures were identified in 80 (54%). Primary outcome definitions, outcome assessment timeframes and the planned sample size were modified in 28 (19%), 12 (8%) and 65 (45%) of registry entries, respectively; of which 21 (75%), 11 (92%), and 33 (51%), respectively, were not reported in the related publications. There were no significant associations between modifications in registry entries and study characteristics.

CONCLUSIONS

Approximately half of trials published in influential medical journals present changes to the design while patient accrual is ongoing, and two thirds of them are unreported. Justification for such modifications should be reported more clearly. Reviewers, editors and readers should consult ClinicalTrials.gov for a more comprehensive report of the evolution of key study methods.

Reporting infections in clinical trials of patients with haematological malignancies

BACKGROUND

Infections are common among patients treated for haematological malignancies and are associated with significant morbidity and mortality. The completeness of reporting infectious complications in randomized controlled trials (RCTs) assessing treatments for haematological malignancies is unknown.

OBJECTIVES

We aimed to evaluate the completeness of reporting infectious complications in RCTs assessing treatments for haematological malignancies.

DATA SOURCE

A systematic literature search was performed in PubMed database.

STUDY ELIGIBILITY CRITERIA AND PARTICIPANTS

All primary published phase II/III RCTs between September 2016 and September 2018 evaluating treatments for haematological malignancies in adult patients were included.

INTERVENTION

Reporting infectious complications.

METHODS

A systematic review was conducted to evaluate the completeness of reporting. Study characteristics and data concerning reporting of infectious complications were collected by two independent reviewers. Quality of reporting was assessed using a modification of the CONSORT extension checklist for harms, including 15 items.

RESULTS

One-hundred and seven RCTs were included. Most trials (97; 91%) provided some report on infections. Approximately half reported on each of pneumonia, sepsis and neutropenic fever; 12 trials (11%) reported on fungal infections. Only nine trials (8%) listed infections by type of pathogen (i.e. bacterial, fungal or viral) and 48 (45%) by source/type of infection (i.e. pneumonia, urinary tract infection, etc.). Most trials did not address infections in their title, abstract, introduction or discussion. Median number of items of the CONSORT modification reported was 7 points, (interquartile range (IQR) 6-9) for all included trials, with lower median for 34 acute leukaemia trials (median 6, IQR 5-8).

CONCLUSIONS

Most trials evaluating treatment for haematological malignancies provide some data relating to infectious complications. The reports are mostly incomplete and rarely provided in a structured presentation.