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.目的：临床试验注册可提升科研透明度，但泌尿外科学等专科领域的临床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临床试验注册的倡导情况，并考察该领域的随机对照试验（randomized controlled trials, RCTs）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。 研究场景：首先，我们评估了《期刊引证报告2009》（2010年12月收录）中收录的泌尿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种，均为高影响因子期刊：其中一组要求以临床试验注册作为论文发表的前提条件，另一组则未提及该要求。随后，我们通过MEDLINE数据库检索2009年（2011年1月）这10种期刊上发表的RCTs，并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，检索未标注注册信息的RCTs（2011年1-3月）。两名研究者独立评估关于临床试验注册的编辑建议，并甄别纳入研究的RCTs。 结果：纳入分析的55种期刊中，26种（47.3%）提及了临床试验注册相关的编辑建议。高影响因子期刊更倾向于直接提及临床试验注册要求（p=0.015）。2009年发表的106项RCTs中，63项完成了注册（59.4%），2005年后注册率呈显著上升趋势（83.3%，p=0.035）。在提及并要求临床试验注册的期刊上发表的RCTs中，注册率为71.4%（30/42）；而在未直接提及临床试验注册要求的期刊上发表的RCTs，注册率为51.6%（33/64），二者差异具有统计学意义（p=0.04）。 结论：作者指南中明确临床试验注册要求，可显著提升RCTs的注册比例。高影响因子期刊更倾向于提及临床试验注册相关要求。不过我们认为，保障临床试验注册并非仅为期刊编辑的责任。医学科研人员应认识到，临床试验注册是提升科研透明度的必要举措。