Clinical Epidemiology Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, CT 06516, USA.
Am J Respir Crit Care Med. 2013 Jun 1;187(11):1167-72. doi: 10.1164/rccm.201303-0521OE.
Individual studies in patient-oriented research, whether described as "comparative effectiveness" or using other terms, are based on underlying methodological designs. A simple taxonomy of study designs includes randomized controlled trials on the one hand, and observational studies (such as case series, cohort studies, and case-control studies) on the other. A rigid hierarchy of these design types is a fairly recent phenomenon, promoted as a tenet of "evidence-based medicine," with randomized controlled trials receiving gold-standard status in terms of producing valid results. Although randomized trials have many strengths, and contribute substantially to the evidence base in clinical care, making presumptions about the quality of a study based solely on category of research design is unscientific. Both the limitations of randomized trials as well as the strengths of observational studies tend to be overlooked when a priori assumptions are made. This essay presents an argument in support of a more balanced approach to evaluating evidence, and discusses representative examples from the general medical as well as pulmonary and critical care literature. The simultaneous consideration of validity (whether results are correct "internally") and generalizability (how well results apply to "external" populations) is warranted in assessing whether a study's results are accurate for patients likely to receive the intervention-examining the intersection of clinical and methodological issues in what can be called a medicine-based evidence approach. Examination of cause-effect associations in patient-oriented research should recognize both the strengths and limitations of randomized trials as well as observational studies.
个体导向研究中的各个研究，无论是被描述为“比较有效性”还是使用其他术语，都基于基础的方法学设计。研究设计的简单分类法一方面包括随机对照试验，另一方面包括观察性研究（如病例系列、队列研究和病例对照研究）。这些设计类型的严格等级制度是最近才出现的现象，被宣传为“循证医学”的原则，随机对照试验在产生有效结果方面具有黄金标准地位。尽管随机试验具有许多优势，并为临床护理的证据基础做出了重大贡献，但仅根据研究设计的类别来假设研究的质量是不科学的。当做出先验假设时，往往会忽略随机试验的局限性以及观察性研究的优势。本文提出了一个支持更平衡的评估证据方法的论点，并讨论了来自一般医学以及肺部和重症监护文献的代表性例子。在评估研究结果是否对可能接受干预的患者准确时，有必要同时考虑有效性（结果是否在“内部”正确）和可推广性（结果在多大程度上适用于“外部”人群），这是在评估研究结果是否准确时应考虑的问题。在个体导向研究中检查因果关系时，应认识到随机试验和观察性研究的优势和局限性。
