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: 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

Prevalence of primary outcome changes in clinical trials registered on ClinicalTrials.gov: a cross-sectional study.

BACKGROUND: An important principle in the good conduct of clinical trials is that a summary of the trial protocol, with a pre-defined primary outcome, should be freely available before the study commences. The clinical trials registry ClinicalTrials.gov provides one method of doing this, and once the trial is registered, any changes made to the primary outcome are documented. The objectives of this study were: to assess the proportion of registered trials on ClinicalTrials.gov that had the primary outcome changed; to assess when the primary outcome was changed in relation to the listed study start and end dates and to assess whether the primary outcome change had any relation to the study sponsor. METHODS: A cross-sectional analysis of all interventional clinical trials registered on ClinicalTrials.gov as of 25 October 2012 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: Our analysis showed that 28229 of 89204 (31.7%) registered studies had their primary outcome changed.  Industry funding was associated with all primary outcome changes, odds ratio (OR)= 1.36, 95% confidence interval (CI)=1.31-1.41, p<0.001; with primary outcome changes after study start date OR=1.37, 95% CI=1.32-1.42, p<0.001; with primary outcome changes after primary completion date OR=1.84, 95% CI=1.75-1.94, p<0.001 and with primary outcome changes after study completion date OR=1.82, 95% CI=1.73-1.91, p<0.001.  Conclusions A significant proportion of interventional trials registered on ClinicalTrials.gov have their primary outcomes altered after the listed study start and completion dates. These changes are associated with funding source

A Systematic Approach to Multiple Breath Nitrogen Washout Test Quality

Background: Accurate estimates of multiple breath washout (MBW) outcomes require correct operation of the device, appropriate distraction of the subject to ensure they breathe in a manner representative of their relaxed tidal breathing pattern, and appropriate interpretation of the acquired data. Based on available recommendations for an acceptable MBW test, we aimed to develop a protocol to systematically evaluate MBW measurements based on these criteria. Methods: 50MBWtest occasions were systematically reviewed for technical elements and whether the breathing pattern was representative of relaxed tidal breathing by an experienced MBW operator. The impact of qualitative and quantitative criteria on inter-observer agreement was assessed across eight MBW operators (n = 20 test occasions, compared using a Kappa statistic). Results: Using qualitative criteria, 46/168 trials were rejected: 16.6%were technically unacceptable and 10.7% were excluded due to inappropriate breathing pattern. Reviewer agreement was good using qualitative criteria and further improved with quantitative criteria from (κ = 0.53– 0.83%) to (κ 0.73–0.97%), but at the cost of exclusion of further test occasions in this retrospective data analysis. Conclusions: The application of the systematic review improved inter-observer agreement but did not affect reported MBW outcomes

Inter-Reviewer Agreement after independent review of 20 test-occasions (61 trials).

<p>Quantitative limits were applied after qualitative review, however each of the two quantitative limits (%CV V_T and V_T limits for size) were applied independently.</p

Summary of technical and qualitative criteria used to evaluate MBW tracings.

<p>Summary of technical and qualitative criteria used to evaluate MBW tracings.</p

Demographics of cross-sectional study population, with results from each step of the quality control criteria applied.

<p>Demographics of cross-sectional study population, with results from each step of the quality control criteria applied.</p

Distribution of CV% V_T for acceptable and unacceptable trials.

<p>Distribution of CV% V_T for acceptable and unacceptable trials.</p