Kristina Lindsley1, Nicole Fusco2, Hannah Teeuw3, Eva Mooij3, Rob Scholten4, Lotty Hooft4. 1. Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands; Cochrane Netherlands, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands; Life Sciences, IBM Watson Health, US,. Electronic address: k.b.lindsley@umcutrecht.nl. 2. Life Sciences, IBM Watson Health, US. 3. Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands. 4. Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands; Cochrane Netherlands, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands.
Abstract
OBJECTIVE: To examine whether clinical trials that have been included in systematic reviews have been registered in clinical trial registers, and, when they have, whether results of the trials were included in the clinical trial register. STUDY DESIGN AND SETTING: Sample of 100 systematic reviews published by the Cochrane Musculoskeletal, Oral, Skin and Sensory (MOSS) Network between 2014 and 2019. RESULTS: We identified 2,000 trials (369,778 participants) from a sample of 100 systematic reviews. The median year of trial publication was 2007. Of 1,177 trials published in 2005 or later, a clinical trial registration record was identified for 368 (31%). Of these registered trials, 135 (37%) were registered prospectively and results were posted for 114 (31%); most registered trials evaluated pharmaceutical interventions (62%). Of trials published in the last 10 years, the proportion of registered trials increased to 38% (261/682). CONCLUSION: Although some improvement in clinical trial registration has been observed in recent years, the proportion of registered clinical trials included in recently published systematic reviews remains less than desirable. Prospective clinical trial registration provides an essential role in assessing the risk of bias and judging the quality of evidence in systematic reviews of intervention safety and effectiveness.
OBJECTIVE: To examine whether clinical trials that have been included in systematic reviews have been registered in clinical trial registers, and, when they have, whether results of the trials were included in the clinical trial register. STUDY DESIGN AND SETTING: Sample of 100 systematic reviews published by the Cochrane Musculoskeletal, Oral, Skin and Sensory (MOSS) Network between 2014 and 2019. RESULTS: We identified 2,000 trials (369,778 participants) from a sample of 100 systematic reviews. The median year of trial publication was 2007. Of 1,177 trials published in 2005 or later, a clinical trial registration record was identified for 368 (31%). Of these registered trials, 135 (37%) were registered prospectively and results were posted for 114 (31%); most registered trials evaluated pharmaceutical interventions (62%). Of trials published in the last 10 years, the proportion of registered trials increased to 38% (261/682). CONCLUSION: Although some improvement in clinical trial registration has been observed in recent years, the proportion of registered clinical trials included in recently published systematic reviews remains less than desirable. Prospective clinical trial registration provides an essential role in assessing the risk of bias and judging the quality of evidence in systematic reviews of intervention safety and effectiveness.