Article type
Year
Abstract
Background: Trial registries such as clinicaltrials.gov typically include information about the status of a randomized controlled trial (RCT), i.e. whether it is ongoing, completed, or discontinued. Trial registries can be a useful resource for systematic reviewers who are searching for unpublished RCTs, such as ongoing or often discontinued RCTs. The accuracy of trial status information in registries has never been investigated.
Objective: To examine whether trial registries accurately label discontinued RCTs as 'discontinued' and provide reasons for RCT discontinuation; and to identify factors associated with inaccurate trial status information.
Methods: Systematic reviews of published RCTs reported as discontinued and registered. We systematically searched MEDLINE and EMBASE (from 2010 to 2014). Pairs of reviewers independently extracted data from publications and corresponding registries using pre-piloted data extraction forms. We performed multivariable regression to identify risk factors for inaccurate trial status information.
Results: We included 173 discontinued RCTs that were registered in various trial registries, most frequently in clinicaltrials.gov (77%). RCTs were mostly discontinued due to slow recruitment (62%), futility (19%), or harm (17%). Of the 173 discontinued RCTs, 45% were accurately labelled as discontinued; the remaining RCTs were wrongly labelled as completed (40%), suspended (9%), on-going (5%), or not started yet (1%). Most RCTs that were accurately labelled also provided the accurate reason for discontinuation (57/77, 74%; Table 1). Significantly, accurate registration of trial status became more frequent over time (adjusted odds ratio 1.16 per year; 95% confidence interval 1.04 to 1.3) whereas trial features such as industry sponsorship, multiple centers, or sample size were not significantly associated with accurate trial status information.
Conclusion: Less than half of published discontinued RCTs were accurately labelled as discontinued in registries. Systematic reviewers searching trial registries for eligible trials should view trial status information with caution.
Objective: To examine whether trial registries accurately label discontinued RCTs as 'discontinued' and provide reasons for RCT discontinuation; and to identify factors associated with inaccurate trial status information.
Methods: Systematic reviews of published RCTs reported as discontinued and registered. We systematically searched MEDLINE and EMBASE (from 2010 to 2014). Pairs of reviewers independently extracted data from publications and corresponding registries using pre-piloted data extraction forms. We performed multivariable regression to identify risk factors for inaccurate trial status information.
Results: We included 173 discontinued RCTs that were registered in various trial registries, most frequently in clinicaltrials.gov (77%). RCTs were mostly discontinued due to slow recruitment (62%), futility (19%), or harm (17%). Of the 173 discontinued RCTs, 45% were accurately labelled as discontinued; the remaining RCTs were wrongly labelled as completed (40%), suspended (9%), on-going (5%), or not started yet (1%). Most RCTs that were accurately labelled also provided the accurate reason for discontinuation (57/77, 74%; Table 1). Significantly, accurate registration of trial status became more frequent over time (adjusted odds ratio 1.16 per year; 95% confidence interval 1.04 to 1.3) whereas trial features such as industry sponsorship, multiple centers, or sample size were not significantly associated with accurate trial status information.
Conclusion: Less than half of published discontinued RCTs were accurately labelled as discontinued in registries. Systematic reviewers searching trial registries for eligible trials should view trial status information with caution.