Papanikolaou Panagiotis N, Ioannidis John P A
Clinical Trials and Evidence-Based Medicine, Department of Hygiene and Epidemiology, University of Ioannina School of Medicine, Ioannina, Greece.
Am J Med. 2004 Oct 15;117(8):582-9. doi: 10.1016/j.amjmed.2004.04.026.
To assess how frequently systematic reviews of randomized controlled trials convey large-scale evidence on specific, well-defined adverse events.
We searched the Cochrane Database of Systematic Reviews for reviews containing quantitative data on specific, well-defined harms for at least 4000 randomized subjects, the minimum sample required for adequate power to detect an adverse event due to an intervention in 1% of subjects. Main outcome measures included the number of reviews with eligible large-scale data on adverse events, the number of ineligible reviews, and the magnitude of recorded harms (absolute risk, relative risk) based on large-scale evidence.
Of 1727 reviews, 138 included evidence on > or =4000 subjects. Only 25 (18%) had eligible data on adverse events, while 77 had no harms data, and 36 had data on harms that were nonspecific or pertained to <4000 subjects. Of 66 specific adverse events for which there were adequate data in the 25 eligible reviews, 25 showed statistically significant differences between comparison arms; most pertained to serious or severe adverse events and absolute risk differences <4%. In 29% (9/31) of a sample of large trials in reviews with poor reporting of harms, specific harms were presented adequately in the trial reports but were not included in the systematic reviews.
Systematic reviews can convey useful large-scale information on adverse events. Acknowledging the importance and difficulties of studying harms, reporting of adverse effects must be improved in both randomized trials and systematic reviews.
评估随机对照试验的系统评价在传达关于特定、明确界定的不良事件的大规模证据方面的频率。
我们在Cochrane系统评价数据库中检索了包含至少4000名随机受试者的特定、明确界定的危害的定量数据的系统评价，这是检测1%受试者因干预导致不良事件所需的足够效力的最小样本量。主要结局指标包括有符合条件的不良事件大规模数据的系统评价数量、不符合条件的系统评价数量以及基于大规模证据记录的危害程度（绝对风险、相对风险）。
在1727项系统评价中，138项包含了≥4000名受试者的证据。只有25项（18%）有符合条件的不良事件数据，77项没有危害数据，36项有非特定或涉及<4000名受试者的危害数据。在25项符合条件的系统评价中有足够数据的66种特定不良事件中，25种在比较组之间显示出统计学显著差异；大多数涉及严重或重度不良事件，绝对风险差异<4%。在危害报告不佳的系统评价中的一个大型试验样本中，29%（9/31）的试验报告中充分呈现了特定危害，但未纳入系统评价。
系统评价可以传达关于不良事件的有用大规模信息。认识到研究危害的重要性和困难，随机试验和系统评价中的不良反应报告都必须改进。
