TY - JOUR
T1 - Clinical trial registration was associated with lower risk of bias compared with non-registered trials among trials included in systematic reviews
AU - Lindsley, Kristina
AU - Fusco, Nicole
AU - Li, Tianjing
AU - Scholten, Rob
AU - Hooft, Lotty
N1 - Funding Information:
Conflicts of interest: Kristina Lindsley was employed by IQVIA, Inc., and Nicole Fusco was employed by Xcenda, LLC during the time period that the study was conducted; however, these organizations had no role in the concept, design, analysis, interpretation, presentation, or funding of the study. Kristina Lindsley, Rob Scholten, and Lotty Hooft are affiliated with Cochrane Netherlands; Kristina Lindsley is a contributing author with the Cochrane Eyes and Vision Group; and Tianjing Li is a coordinating editor for the Cochrane Eyes and Vision Group. There are no known financial conflicts of interest. Funding: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.
Publisher Copyright:
© 2022 The Authors
PY - 2022/5
Y1 - 2022/5
N2 - Objective: To examine the association between clinical trial registration and risk of bias in clinical trials that have been included in systematic reviews. As a secondary objective, we evaluated the risk of bias among trials registered prospectively vs. retrospectively. Method: Clinical trials published in 2005 or after included in a sample of 100 Cochrane systematic reviews published from 2014-2019. Results: Of 1,177 clinical trials identified, we verified 368 (31%) had been registered, of which 135 (36.7%) were registered prospectively (i.e., before or up to 1 month after enrollment of the first participant). Across the bias domains (one bias assessment for each domain per trial), the percentage of trials at low risk ranged from 29% to 58%; unclear risk ranged from to 26% to 61% and high risk ranged from 2% to 38%. Trials that had been registered had less high or unclear risk of bias in five domains: random sequence generation (univariate risk ratio [RR] 0.69, 95% confidence interval [95% CI] 0.58-0.81), allocation concealment (RR 0.64, 95% CI 0.57-0.72), performance bias (RR 0.65, 95% CI 0.58-0.72), detection bias (RR 0.70, 95% CI 0.62-0.78), and reporting bias (RR 0.62, 95% CI 0.53-0.73). An association between clinical trial registration and high or unclear risk of attrition bias could not be demonstrated nor refuted (RR 1.02, 95% CI 0.89-1.17). It also was observed in terms of overall risk of bias, that registered trials had less high or unclear overall risk of bias than trials that had not been registered (univariate RR 0.29, 95% CI 0.19-0.46). Prospective clinical trial registration was associated with low risks of selection bias due to inadequate allocation concealment, performance bias, and detection bias compared with retrospective clinical trial registration. Conclusion: In a large sample of clinical trials included in recently published systematic reviews of interventions, clinical trial registration was associated with low risk of bias for five of the six domains examined.
AB - Objective: To examine the association between clinical trial registration and risk of bias in clinical trials that have been included in systematic reviews. As a secondary objective, we evaluated the risk of bias among trials registered prospectively vs. retrospectively. Method: Clinical trials published in 2005 or after included in a sample of 100 Cochrane systematic reviews published from 2014-2019. Results: Of 1,177 clinical trials identified, we verified 368 (31%) had been registered, of which 135 (36.7%) were registered prospectively (i.e., before or up to 1 month after enrollment of the first participant). Across the bias domains (one bias assessment for each domain per trial), the percentage of trials at low risk ranged from 29% to 58%; unclear risk ranged from to 26% to 61% and high risk ranged from 2% to 38%. Trials that had been registered had less high or unclear risk of bias in five domains: random sequence generation (univariate risk ratio [RR] 0.69, 95% confidence interval [95% CI] 0.58-0.81), allocation concealment (RR 0.64, 95% CI 0.57-0.72), performance bias (RR 0.65, 95% CI 0.58-0.72), detection bias (RR 0.70, 95% CI 0.62-0.78), and reporting bias (RR 0.62, 95% CI 0.53-0.73). An association between clinical trial registration and high or unclear risk of attrition bias could not be demonstrated nor refuted (RR 1.02, 95% CI 0.89-1.17). It also was observed in terms of overall risk of bias, that registered trials had less high or unclear overall risk of bias than trials that had not been registered (univariate RR 0.29, 95% CI 0.19-0.46). Prospective clinical trial registration was associated with low risks of selection bias due to inadequate allocation concealment, performance bias, and detection bias compared with retrospective clinical trial registration. Conclusion: In a large sample of clinical trials included in recently published systematic reviews of interventions, clinical trial registration was associated with low risk of bias for five of the six domains examined.
KW - Evidence synthesis
KW - Randomized controlled trial
KW - Research methods
KW - Risk of bias
KW - Systematic review
KW - Trial registration
UR - http://www.scopus.com/inward/record.url?scp=85125574768&partnerID=8YFLogxK
U2 - 10.1016/j.jclinepi.2022.01.012
DO - 10.1016/j.jclinepi.2022.01.012
M3 - Article
C2 - 35081449
SN - 0895-4356
VL - 145
SP - 164
EP - 173
JO - Journal of Clinical Epidemiology
JF - Journal of Clinical Epidemiology
ER -