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，但泌尿外科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，并考察该领域随机对照试验（randomized controlled trial, RCT）的实际注册落实情况。
研究设计：已发表试验的横断面研究。
研究实施与检索方案：首先，我们评估了2009年《期刊引证报告》（Journal Citation Reports 2009）收录的泌尿相关期刊的作者指南（检索时间：2010年12月）。随后，将符合条件的期刊分为两组，每组各5本，均为高影响因子期刊，一组要求将试验注册作为发表前置条件，另一组未提及该要求。接着，我们通过MEDLINE数据库检索2009年发表于这10本期刊的随机对照试验（检索时间：2011年1月）；针对未检索到注册信息的随机对照试验，通过世界卫生组织国际临床试验注册平台（International Clinical Trials Registry Platform, ICTRP）的临床试验元搜索界面开展补充检索（检索时间：2011年1-3月）。由两名研究者独立评估试验注册相关的编辑指导意见，并识别纳入的随机对照试验。
研究结果：纳入分析的55本期刊中，26本（47.3%）包含试验注册相关的编辑指导意见。高影响因子期刊更倾向于直接明确提及试验注册要求（p=0.015）。2009年发表的106项随机对照试验中，63项完成了注册（占比59.4%），且2005年后注册率呈显著上升趋势（83.3%，p=0.035）。在明确提及并要求试验注册的期刊上发表的随机对照试验中，注册率为71.4%（30/42）；而在未直接提及试验注册要求的期刊上发表的随机对照试验，注册率仅为51.6%（33/64），两组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随机对照试验的注册比例。高影响因子期刊更倾向于提及试验注册相关要求。但本研究提示，保障试验注册并非仅为期刊编辑的责任，医学科研工作者应认识到试验注册对于提升研究透明度的必要性。