Odutayo Ayodele, Emdin Connor A, Hsiao Allan J, Shakir Mubeen, Copsey Bethan, Dutton Susan, Chiocchia Virginia, Schlussel Michael, Dutton Peter, Roberts Corran, Altman Douglas G, Hopewell Sally
Centre for Statistics in Medicine, Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences, University of Oxford, Oxford OX3 7LD, UK
Applied Health Research Centre (AHRC), Li Ka Shing Knowledge Institute of St Michael's Hospital, Toronto, ON, Canada.
BMJ. 2017 Mar 14;356:j917. doi: 10.1136/bmj.j917.
To assess whether randomised controlled trials (RCTs) that were registered were less likely to report positive study findings compared with RCTs that were not registered and whether the association varied by funding source. Cross sectional study. All primary RCTs published in December 2012 and indexed in PubMed by November 2013. Trial registration was determined based on the report of a trial registration number in published RCTs or the identification of the trial in a search of trial registries. Trials were separated into prospectively and retrospectively registered studies. Association between trial registration and positive study findings. 1122 eligible RCTs were identified, of which 593 (52.9%) were registered and 529 (47.1%) were not registered. Overall, registration was marginally associated with positive study findings (adjusted risk ratio 0.87, 95% confidence interval 0.78 to 0.98), even with stratification as prospectively and retrospectively registered trials (0.87, 0.74 to 1.03 and 0.88, 0.78 to 1.00, respectively). The interaction term between overall registration and funding source was marginally statistically significant and relative risk estimates were imprecise (0.75, 0.63 to 0.89 for non-industry funded and 1.03, 0.79 to 1.36 for industry funded, P interaction=0.046). Furthermore, a statistically significant interaction was not maintained in sensitivity analyses. Within each stratum of funding source, relative risk estimates were also imprecise for the association between positive study findings and prospective and retrospective registration. Among published RCTs, there was little evidence of a difference in positive study findings between registered and non-registered clinical trials, even with stratification by timing of registration. Relative risk estimates were imprecise in subgroups of non-industry and industry funded trials.
评估已注册的随机对照试验（RCT）与未注册的RCT相比，报告阳性研究结果的可能性是否更低，以及这种关联是否因资金来源而异。横断面研究。2012年12月发表并于2013年11月在PubMed上索引的所有主要RCT。根据已发表的RCT中试验注册号的报告或在试验注册库搜索中对试验的识别来确定试验注册情况。试验被分为前瞻性注册和回顾性注册研究。试验注册与阳性研究结果之间的关联。共识别出1122项符合条件的RCT，其中593项（52.9%）已注册，529项（47.1%）未注册。总体而言，注册与阳性研究结果略有关联（调整风险比0.87，95%置信区间0.78至0.98），即使将试验分层为前瞻性和回顾性注册试验时也是如此（分别为0.87，0.74至1.03和0.88，0.78至1.00）。总体注册与资金来源之间的交互项在统计学上略有显著意义，相对风险估计不精确（非行业资助的为0.75，0.63至0.89，行业资助的为1.03，0.79至1.36，P交互作用 = 0.046）。此外，在敏感性分析中未维持统计学上显著的交互作用。在每个资金来源层内，阳性研究结果与前瞻性和回顾性注册之间关联的相对风险估计也不精确。在已发表的RCT中，几乎没有证据表明注册和未注册的临床试验在阳性研究结果方面存在差异，即使按注册时间分层也是如此。在非行业和行业资助试验的亚组中，相对风险估计不精确。
