Wallace David K
Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina, USA.
Am Orthopt J. 2010;60:2-5. doi: 10.3368/aoj.60.1.2.
Evidence-based medicine is the practice of making medical decisions based on evidence gained from applying the scientific method. Published studies are evaluated using three key questions: "Are the results valid?"; "What are the results?"; and "Can the results be applied to my patients?" The hierarchy of study methods for obtaining evidence is, in order from least to most useful: laboratory research, editorials, case reports and series, case-control studies, cohort studies, and randomized clinical trials. Retrospective case series can suffer from problems such as selection of a biased sample, mixing of treatment effects, and lack of control group. Randomized clinical trials (and meta-analyses of multiple trials) provide the highest level of evidence because randomization limits confounding and prevents bias of treatment assignment. In addition, randomized trials have standardization of interventions, prospective data collection, and masked outcome measures. Although every question cannot be addressed by a randomized clinical trial, the best available evidence should be sought and used to guide treatments.
循证医学是基于应用科学方法所获得的证据来做出医疗决策的实践。已发表的研究通过三个关键问题进行评估：“结果有效吗？”；“结果是什么？”；以及“结果能应用于我的患者吗？”获取证据的研究方法层次结构，从最没用的到最有用的依次为：实验室研究、社论、病例报告及系列、病例对照研究、队列研究和随机临床试验。回顾性病例系列可能存在诸如选择有偏差的样本、治疗效果混淆以及缺乏对照组等问题。随机临床试验（以及多个试验的荟萃分析）提供最高级别的证据，因为随机化限制了混杂因素并防止治疗分配产生偏差。此外，随机试验具有干预措施的标准化、前瞻性数据收集和盲法结局测量。尽管并非每个问题都能通过随机临床试验来解决，但应寻求并使用最佳可得证据来指导治疗。
