Abstract
Since 2005, International Committee of Medical Journal Editors (ICMJE) member journals have required that clinical trials be registered in publicly available trials registers before they are considered for publication. The research explores whether it is adequate, when searching to inform systematic reviews, to search for relevant clinical trials using only public trials registers and to identify the optimal search approaches in trials registers. A search was conducted in ClinicalTrials.gov and the International Clinical Trials Registry Platform (ICTRP) for research studies that had been included in eight systematic reviews. Four search approaches (highly sensitive, sensitive, precise, and highly precise) were performed using the basic and advanced interfaces in both resources. On average, 84% of studies were not listed in either resource. The largest number of included studies was retrieved in ClinicalTrials.gov and ICTRP when a sensitive search approach was used in the basic interface. The use of the advanced interface maintained or improved sensitivity in 16 of 19 strategies for Clinicaltrials.gov and 8 of 18 for ICTRP. No single search approach was sensitive enough to identify all studies included in the 6 reviews. Trials registers cannot yet be relied upon as the sole means to locate trials for systematic reviews. Trials registers lag behind the major bibliographic databases in terms of their search interfaces. For systematic reviews, trials registers and major bibliographic databases should be searched. Trials registers should be searched using sensitive approaches, and both the registers consulted in this study should be searched.
Highlights
Since July 2005, all International Committee of Medical Journal Editors (ICMJE) member journals have required that clinical trials must be registered in publicly available trials registers before they are considered for publication [1]
The eight systematic reviews addressed a variety of interventions and conditions: & anti-fibrinolytic use for minimising perioperative allogeneic blood transfusion [9], & preoperative autologous donation for minimising perioperative allogeneic blood transfusion [10], & parenteral versus oral iron therapy for adults and children with chronic kidney disease [11], & intracutaneous or subcutaneous sterile water injection compared with blinded controls for pain management in labour [12], & intramedullary nailing for tibial shaft fractures in adults [13], & tranexamic acid for upper gastrointestinal bleeding [14], & intravesical gemcitabine for non-muscle invasive bladder cancer [15], and & continuous glucose monitoring systems for type 1 diabetes mellitus [16]
The remaining 7 Cochrane systematic reviews (CSRs) varied in terms of the proportion of their included studies that could be identified in the registers
Summary
Since 2005, International Committee of Medical Journal Editors (ICMJE) member journals have required that clinical trials be registered in publicly available trials registers before they are considered for publication. Since July 2005, all International Committee of Medical Journal Editors (ICMJE) member journals have required that clinical trials must be registered in publicly available trials registers before they are considered for publication [1]. Such registration is designed to ensure that trial details are available to all: health care professionals, patients, librarians, program managers, and researchers, including systematic reviewers. If all trials are recorded in registers, the need to search other resources
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