Delaney Joseph A C, Daskalopoulou Stella S, Suissa Samy
Department of Biostatistics, Collaborative Health Studies Coordinating Center, University of Washington, Seattle, WA 98115 USA.
Pharmacoepidemiol Drug Saf. 2009 Jan;18(1):1-6. doi: 10.1002/pds.1676.
Observational studies of the effect of beta-blockers on all-cause mortality after an acute myocardial infarction (AMI) have tended to overestimate the effectiveness of this treatment.
To compare the estimates of the effect of beta-blocker use on mortality post-AMI derived from a traditional adjusted regression model with those from a marginal structural model.
A population-based cohort spanning the period of 2002-2004 was formed from the United Kingdom General Practice Research Database (GPRD). The cohort included all subjects who survived 90 days after their first AMI, who were then followed for 9 months. beta-Blocker use and blood pressure were identified in both the 90-day period before and the 90-day period after the AMI. Rate ratios (RR) were estimated using pooled logistic regression.
The cohort included 9939 participants who survived 90 days after their AMI, of whom 633 died during the 9-month follow-up. Over 23% were taking beta-blockers pre-AMI, compared with 71% post-AMI. Using the traditional adjusted regression analysis, the RR of death with post-AMI beta-blocker use was 0.54 (95% confidence interval (CI): 0.45-0.67), while using the inverse probability of treatment weighting (IPTW) model it was 0.72 (95%CI: 0.61-0.84). The IPTW estimate is compatible with the estimate derived from a meta-analysis of randomized controlled trials (RCTs) while the adjusted regression estimate exaggerates the effectiveness.
Observational studies of the association of anti-hypertensive medications with all-cause mortality should consider adding a marginal structural model to their armamentarium of data analysis.
关于β受体阻滞剂对急性心肌梗死（AMI）后全因死亡率影响的观察性研究往往高估了这种治疗方法的有效性。
比较传统调整回归模型与边际结构模型得出的β受体阻滞剂使用对AMI后死亡率影响的估计值。
基于英国全科医疗研究数据库（GPRD）形成了一个涵盖2002年至2004年期间的人群队列。该队列包括所有在首次AMI后存活90天的受试者，随后对其进行9个月的随访。在AMI前90天和AMI后90天期间确定β受体阻滞剂的使用情况和血压。使用汇总逻辑回归估计率比（RR）。
该队列包括9939名在AMI后存活90天的参与者，其中633人在9个月的随访期间死亡。超过23%的人在AMI前服用β受体阻滞剂，而在AMI后这一比例为71%。使用传统调整回归分析，AMI后使用β受体阻滞剂的死亡RR为0.54（95%置信区间（CI）：0.45 - 0.67），而使用治疗权重逆概率（IPTW）模型时为0.72（95% CI：0.61 - 0.84）。IPTW估计值与随机对照试验（RCT）的荟萃分析得出的估计值相符，而调整回归估计值夸大了有效性。
关于抗高血压药物与全因死亡率关联的观察性研究应考虑在其数据分析方法中增加边际结构模型。
