DOES MORE INTENSIVE TREATMENT OF ACUTE MYOCARDIAL-INFARCTION IN THE ELDERLY REDUCE MORTALITY - ANALYSIS USING INSTRUMENTAL VARIABLES
DOES MORE INTENSIVE TREATMENT OF ACUTE MYOCARDIAL-INFARCTION IN THE ELDERLY REDUCE MORTALITY - ANALYSIS USING INSTRUMENTAL VARIABLES
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DOI：
10.1001/jama.272.11.859
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发表时间：
1994-09-21
影响因子：
120.7
通讯作者：
NEWHOUSE, JP
中科院分区：
文献类型：
--
作者：
MCCLELLAN, M;MCNEIL, BJ;NEWHOUSE, JP
目的：-确定更密集的治疗对老年急性心肌梗死(AMI)患者死亡率的影响。设计-使用不同距离作为工具变量来分析递增治疗效果，以解释观察性医疗保险索赔数据(1987-1991年)中未观察到的病例组合差异(选择偏差)。主要结果衡量标准-急性心肌梗死后4年的存活率。结果：接受不同治疗的患者在可观察和不可观察的健康特征上存在差异，根据可观察到的差异调整的标准方法对治疗效果的估计有偏差。患者到不同类型医院的不同距离是急性心肌梗死患者接受治疗强度的强大独立预测因素，而且似乎与健康状况无关。因此，不同的距离大致将患者随机分配到接受强化治疗的不同可能性。对仅在不同距离上存在差异的患者组的比较表明，在急性心肌梗死后1至4年，医疗保险患者增加使用侵入性程序对死亡率的影响至多为5个百分点；这一增长是在住院的第一天实现的，因此似乎可归因于程序以外的其他治疗方法。入院治疗大量急性心肌梗死患者与4年死亡率的影响不到1个百分点有关，同样出现在第一天。生活在农村地区的患者在控制了较少获得强化治疗的情况后，急性死亡率增加了0.6个百分点。结论：对于老年急性心肌梗死患者，最影响长期生存的治疗方面与入院前24小时内的护理有关。在边缘患者中，更多地使用导尿术和血管重建术对生存的好处似乎微乎其微。
Objective.-To determine the effect of more intensive treatments on mortality in elderly patients with acute myocardial infarction (AMI).Design.-Analysis of incremental treatment effects using differential distances as instrumental variables to account for unobserved case-mix variation (selection bias) in observational Medicare claims data (1987 through 1991).Main Outcome Measures.-Survival to 4 years after AMI.Results.-Patients who receive different treatments differ in observable and unobservable health characteristics, biasing estimates of treatment effects based on standard methods of adjusting for observable differences. Patients' differential distances to alternative types of hospitals are strong independent predictors of how intensively an AMI patient will be treated and appear uncorrelated with health status. Thus, differential distances approximately randomize patients to different likelihoods of receiving intensive treatments. Comparisons of patient groups that differ only in differential distances show that the impact on mortality at 1 to 4 years after AMI of the incremental (''marginal'') use of invasive procedures in Medicare patients was at most 5 percentage points; this gain was achieved during the first day of hospitalization and therefore appears attributable to treatments other than the procedures. Admission to a hospital treating a high volume of AMI patients was associated with an effect on mortality at 4 years of less than 1 percentage point, again arising on day 1. Patients living in rural areas experienced acute mortality that was an additional 0.6 percentage-point higher, after controlling for less access to intensive treatments.Conclusions.-For elderly patients with AMI, the aspects of treatment most affecting long-term survival relate to care within the first 24 hours of admission. The survival benefits from greater use of catheterization and revascularization procedures appear minimal in marginal patients.