Data from: Do urology journals enforce trial registration? A cross-sectional study of published trials

OBJECTIVES: Trial registration can increase scientific transparency, but its implementation in specialty fields such as urology is unclear. We aimed to assess the endorsement of trial registration in the author instructions of urology-related journals and to assess whether randomized controlled trials (RCTs) in the field were effectively registered. DESIGN: Cross-sectional study of published trials. SETTING: We first assessed the author instructions of urology-related journals indexed in ‘Journal Citation Reports 2009’ (12/2010). Second, we divided the results into two groups of five journals each, all with high impact factors either requiring or not mentioning trial registration as a precondition for publication. We then performed a MEDLINE search to identify RCTs published in these 10 journals in 2009 (01/2011) and searched the clinical trials meta-search interface of the World Health Organization (ICTRP) for RCTs without information about registration (01–03/2011). Two authors independently assessed information regarding editorial advice about trial registration and identified the RCTs. RESULTS: Of 55 journals included, 26 (47.3%) contained some editorial advice about trial registration. Journals with high impact factors were more likely to mention trial registration directly (p=0.015). Of 106 RCTs published in 2009, 63 were registered (59.4%) with a tendency to an increase after 2005 (83.3%, p=0.035). 71.4% (30/42) of the RCTs that were published in journals mentioning and requiring registration, and 51.6% (33/64) of the RCTs that were published in journals that did not mention trial registration directly were registered. This difference was statistically significant (p=0.04). CONCLUSION: A statement of trial registration in author instructions resulted in a higher proportion of registered RCTs. Journals with high impact factors were more likely to mention trial registration. We suggest, though, that ensuring trial registration is not the responsibility only of the editors. Medical scientists should realize that trial registration is necessary to contribute to transparency in research.

研究目的：试验注册可提升科研透明度，但泌尿学等专科领域的试验注册实施现状尚不明确。本研究旨在评估泌尿学相关期刊作者指南中对试验注册的倡导情况，并考察该领域的随机对照试验（Randomized Controlled Trial, RCT）是否得到有效注册。研究设计：针对已发表试验的横断面研究。研究实施场景：首先，我们评估了2009年《期刊引证报告（Journal Citation Reports）》收录的、截至2010年12月的泌尿学相关期刊的作者指南。其次，我们将纳入的期刊分为两组，每组各5本，均为高影响因子期刊，其中一组要求将试验注册作为发表前提，另一组未提及该要求。随后，我们在MEDLINE数据库中检索2009年（2011年1月）发表于这10本期刊的RCT，并通过世界卫生组织临床试验元检索平台（International Clinical Trials Registry Platform, ICTRP）检索未提及注册信息的RCT（检索时间为2011年1月至3月）。两名研究者独立评估有关试验注册的编辑指导意见，并甄别纳入RCT。研究结果：纳入分析的55本期刊中，26本（47.3%）包含了关于试验注册的编辑指导意见。高影响因子期刊更倾向于直接提及试验注册要求（p=0.015）。2009年发表的106项RCT中，63项完成了注册（59.4%），且2005年后RCT注册率呈上升趋势（83.3%，p=0.035）。在提及并要求试验注册的期刊中发表的RCT，其注册率为71.4%（30/42）；在未直接提及试验注册要求的期刊中发表的RCT，注册率为51.6%（33/64），二者差异具有统计学意义（p=0.04）。研究结论：作者指南中明确试验注册要求可提升RCT的注册比例。高影响因子期刊更易提及试验注册要求。但本研究提示，确保试验注册并非仅为编辑的责任。医学科研工作者应认识到，试验注册对于提升科研透明度具有必要性。