Feinstein A R, Horwitz R I
Department of Medicine, Yale University School of Medicine, New Haven, Connecticut 06510, USA.
Am J Med. 1997 Dec;103(6):529-35. doi: 10.1016/s0002-9343(97)00244-1.
The proposed practice of "evidence-based medicine," which calls for careful clinical judgment in evaluating the "best available evidence," should be differentiated from the special collection of data regarded as suitable evidence. Although the proposed practice does not seem new, the new collection of "best available" information has major constraints for the care of individual patients. Derived almost exclusively from randomized trials and meta-analyses, the data do not include many types of treatments or patients seen in clinical practice; and the results show comparative efficacy of treatment for an "average" randomized patient, not for pertinent subgroups formed by such cogent clinical features as severity of symptoms, illness, co-morbidity, and other clinical nuances. The intention-to-treat analyses do not reflect important post-randomization events leading to altered treatment; and the results seldom provide suitable background data when therapy is given prophylactically rather than remedially, or when therapeutic advantages are equivocal. Randomized trial information is also seldom available for issues in etiology, diagnosis, and prognosis, and for clinical decisions that depend on pathophysiologic changes, psychosocial factors and support, personal preferences of patients, and strategies for giving comfort and reassurance. The laudable goal of making clinical decisions based on evidence can be impaired by the restricted quality and scope of what is collected as "best available evidence." The authoritative aura given to the collection, however, may lead to major abuses that produce inappropriate guidelines or doctrinaire dogmas for clinical practice.
“循证医学”的倡导做法要求在评估“最佳现有证据”时进行审慎的临床判断，应将其与被视为合适证据的特殊数据收集区分开来。尽管所倡导的做法似乎并非新事物，但新收集的“最佳现有”信息在个体患者护理方面存在重大限制。这些数据几乎完全来自随机试验和荟萃分析，不包括临床实践中所见的许多类型的治疗方法或患者；而且结果显示的是针对“平均”随机患者的治疗比较疗效，而非针对由症状严重程度、疾病、合并症及其他临床细微差别等有力临床特征形成的相关亚组。意向性分析并未反映导致治疗改变的重要随机化后事件；而且当进行预防性而非补救性治疗时，或者当治疗优势不明确时，结果很少能提供合适的背景数据。关于病因、诊断和预后以及依赖病理生理变化、心理社会因素与支持、患者个人偏好以及给予安慰和保证策略的临床决策，随机试验信息也很少可得。基于证据做出临床决策这一值得称赞的目标可能会因被收集为“最佳现有证据”的内容质量和范围受限而受到损害。然而，赋予该收集内容的权威光环可能会导致重大滥用，从而产生不适当的临床实践指南或教条主义信条。
