Tannen Richard L, Weiner Mark G, Marcus Sue M
Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA, USA.
J Clin Epidemiol. 2006 Mar;59(3):254-64. doi: 10.1016/j.jclinepi.2005.08.008.
To determine the validity of outcome research using a primary care practice database by comparing a randomized controlled trial (RCT) with a simulated one.
A cohort from the United Kingdom General Practice Research Database (GPRD) was used to simulate the Systolic Hypertension in Europe (Syst-Eur) trial, a study of antihypertensive therapy of isolated systolic hypertension, by replicating all aspects of that RCT (selection criteria, study time frame, treatment, and outcomes) except randomization.
The exposed and unexposed groups in the GPRD study exhibited similar baseline characteristics. Stroke, the primary RCT outcome, decreased significantly in both the RCT (incidence rate ratio IRR = 0.58) and the GPRD study (IRR = 0.68). Myocardial infarction decreased nonsignificantly but similarly in both studies (RCT IRR = 0.70; GPRD IRR = 0.74). With the GPRD study extended for 3 years more, myocardial infarction decreased significantly, comparable to findings from the Systolic Hypertension in the Elderly Program (SHEP), another RCT similar to Syst-Eur.
The findings support the potential value of clinical databases to investigate treatment effectiveness. RCT simulation using the GPRD may be the most feasible way to assess observational study validity in comparison to RCTs. The extended GPRD study shows the feasibility of using a simulated study to supplement the results of an RCT of limited duration.
通过将一项随机对照试验（RCT）与一项模拟试验进行比较，确定使用初级保健实践数据库进行结果研究的有效性。
来自英国全科医学研究数据库（GPRD）的一个队列被用于模拟欧洲收缩期高血压（Syst-Eur）试验，该试验是一项关于单纯收缩期高血压抗高血压治疗的研究，通过复制该RCT的所有方面（入选标准、研究时间框架、治疗和结果），但不包括随机分组。
GPRD研究中的暴露组和未暴露组表现出相似的基线特征。中风是RCT的主要结果，在RCT（发病率比IRR = 0.58）和GPRD研究（IRR = 0.68）中均显著降低。心肌梗死在两项研究中均有非显著但相似的下降（RCT的IRR = 0.70；GPRD的IRR = 0.74）。将GPRD研究延长3年后，心肌梗死显著下降，与老年收缩期高血压计划（SHEP）的结果相当，SHEP是另一项与Syst-Eur相似的RCT。
这些发现支持临床数据库在研究治疗效果方面的潜在价值。与RCT相比，使用GPRD进行RCT模拟可能是评估观察性研究有效性的最可行方法。延长的GPRD研究表明，使用模拟研究来补充有限期RCT结果的可行性。
