Abstract
Purpose :
To examine the characteristics of randomized clinical trials (RCTs) and trial registration in the field of eyes and vision.
Methods :
We identified RCTs from a random sample of systematic reviews with at least 5 included trials published by the Cochrane Eyes and Vision Group from 2014-2019. Reasons for using Cochrane reviews to identify RCTs were that they are limited to only clinical trials (observational studies that do not require trial registration are excluded) and trial registers are searched in addition to bibliographic databases in all reviews. We report trial characteristics (year of publication, number of participants, clinical area, region, and trial registration) overall and stratified by year of publication. Trial registration data were analyzed only for trials published in 2000, the year that ClinicalTrials.gov was made publicly available, or later. We extracted trial registration numbers reported in the reviews. For trials in which no registration number was provided in the review, we searched ClinicalTrials.gov and the WHO trial portal.
Results :
The 30 randomly selected reviews included 586 trials (median 12.5 per review) and 166,879 participants (median 59.5 per trial). There were 199 (34%) trials published before 2000 and 387 (66%) published from 2000-2017 (table). Prior to 2000, the majority of trials in this sample evaluated corneal and external eye disease (60%) and were conducted in Europe (52%). Since 2000, the trials were spread more evenly across clinical topic area and geographic region. Overall, 104 (27%) trials were registered from 2000-2017. Of these trial registrations, 30 (29%) included results with the registration. An upward trend in registrations was seen after 2005 (5/74; 7%), when the ICMJE recommended that journals require clinical trial registrations for publication, and continued after 2007, when the FDA made the requirement for all applicable trials of drugs, devices, and biologics to be registered (graph).
Conclusions :
Clinical trial registers, such as ClinicalTrials.gov, aim to improve transparency and minimize bias in clinical research. Although trial registration rates are improving, the overall proportion is still low, and even fewer trials have results posted as part of the clinical trial registration record.
This is a 2020 ARVO Annual Meeting abstract.