Comparison of evidence on harms of medical interventions in randomized and nonrandomized studies
Comparison of evidence on harms of medical interventions in randomized and nonrandomized studies
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DOI：
10.1503/cmaj.050873
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发表时间：
2006-02-28
影响因子：
14.6
通讯作者：
Ioannidis, JPA
中科院分区：
文献类型：
--
作者：
Papanikolaou, PN;Christidi, GD;Ioannidis, JPA
背景：有关医疗干预措施主要危害的信息主要来自许可和营销后进行的流行病学研究。与大规模随机试验的数据进行比较有时是可行的。我们将随机试验的证据与流行病学研究的证据进行了比较，以确定它们是否对医疗干预措施的重要危害给出了不同的风险估计。方法：我们针对各种医疗干预措施的明确、具体的危害，这些干预措施的数据已经从大规模随机试验（> 4000 名受试者）中获得。通过 MEDLINE 检索，检索到涉及至少 4000 名受试者的非随机研究，涉及这些相同的危害。我们比较了随机和非随机研究中特定危害的相对风险和绝对风险差异。结果：针对 15 种危害找到了符合条件的非随机研究，这些危害的数据来自针对相同危害的随机试验。 15 个主题中的 13 个研究类型之间的相对风险比较是可行的，8 个主题的绝对风险差异比较是可行的。 13 个主题中的 7 个主题 (54%) 的随机研究和非随机研究之间相对风险的估计增加相差超过 2 倍； 8 个主题中的 5 个主题 (62%) 的绝对风险估计增幅相差超过 2 倍。随机或非随机研究没有明显偏向于估计更大的相对风险，但通常（75% [6/8]）随机试验比非随机研究估计更大的绝对超额伤害风险。 解释：非随机研究在估计绝对伤害风险时通常比较保守。比较和审查从随机和非随机研究中获得的危害证据将很有用。
Background: Information on major harms of medical interventions comes primarily from epidemiologic studies performed after licensing and marketing. Comparison with data from large-scale randomized trials is occasionally feasible. We compared evidence from randomized trials with that from epidemiologic studies to determine whether they give different estimates of risk for important harms of medical interventions.Methods: We targeted well-defined, specific harms of various medical interventions for which data were already available from large-scale randomized trials (> 4000 subjects). Nonrandomized studies involving at least 4000 subjects addressing these same harms were retrieved through a search of MEDLINE. We compared the relative risks and absolute risk differences for specific harms in the randomized and nonrandomized studies.Results: Eligible nonrandomized studies were found for 15 harms for which data were available from randomized trials addressing the same harms. Comparisons of relative risks between the study types were feasible for 13 of the 15 topics, and of absolute risk differences for 8 topics. The estimated increase in relative risk differed more than 2-fold between the randomized and nonrandomized studies for 7 (54%) of the 13 topics; the estimated increase in absolute risk differed more than 2-fold for 5 (62%) of the 8 topics. There was no clear predilection for randomized or nonrandomized studies to estimate greater relative risks, but usually (75% [6/8]) the randomized trials estimated larger absolute excess risks of harm than the nonrandomized studies did.Interpretation: Nonrandomized studies are often conservative in estimating absolute risks of harms. It would be useful to compare and scrutinize the evidence on harms obtained from both randomized and nonrandomized studies.