Analysis of observational studies in the presence of treatment selection bias - Effects of invasive cardiac management on AMI survival using propensity score and instrumental variable methods
Analysis of observational studies in the presence of treatment selection bias - Effects of invasive cardiac management on AMI survival using propensity score and instrumental variable methods
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DOI：
10.1001/jama.297.3.278
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发表时间：
2007-01-17
影响因子：
120.7
通讯作者：
Vermeulen, Marian J.
中科院分区：
文献类型：
--
作者：
Stukel, Therese A.;Fisher, Elliott S.;Vermeulen, Marian J.
背景观察性研究中治疗和未治疗患者之间的结果比较可能会由于组间患者预后的差异而产生偏倚，这通常是由于未观察到的治疗选择偏倚。目的比较4种分析方法，以消除观察性研究中选择偏倚的影响：多变量模型风险调整，倾向评分风险调整，基于倾向的匹配，和工具变量分析。设计，设置，一个全国性的队列，包括122124例老年患者（年龄65-84岁），接受医疗保险，1994-1995年因急性心肌梗死（AMI）住院，并符合心导管插入术的条件。基线图表回顾取自心血管合作项目，并与医疗保险健康管理数据相关联，以提供一组丰富的预后变量。患者随访7年至2001年12月31日，以评估长期生存和心导管插入术之间的关联在30天内入院account.Main结果测量风险调整的相对死亡率使用每一个分析methods.Results患者接受心导管插入术（n = 73 238）是年轻的，有较低的AMI严重程度比那些谁没有。在使用标准的统计风险调整方法调整预后因素后，心导管插入术与死亡率相对降低50（对于多变量模型风险调整：调整的相对风险[RR]，0.51; 95%置信区间[CI]，0.50-0.52;对于倾向评分风险调整：调整的RR，0.54; 95%CI，0.53-0.55;对于基于倾向性的匹配：校正RR，0.54; 95%CI，0.52-0.56）。使用局部导管插入率作为工具，工具变量分析显示死亡率相对下降16%（调整后RR，0.84; 95%CI，0.79-0.90）。随机临床试验显示，常规介入治疗的生存获益在8%~ 21%之间。结论心导管插入术与AMI远期死亡率的观察性相关性对分析方法高度敏感。所有标准的风险调整方法在去除未测量的治疗选择偏倚方面都有相同的局限性。与标准建模相比，工具变量分析可能产生较少的治疗效果偏倚估计，但更适合回答政策问题，而不是具体的临床问题。
Context Comparisons of outcomes between patients treated and untreated in observational studies may be biased due to differences in patient prognosis between groups, often because of unobserved treatment selection biases.Objective To compare 4 analytic methods for removing the effects of selection bias in observational studies: multivariable model risk adjustment, propensity score risk adjustment, propensity-based matching, and instrumental variable analysis.Design, Setting, and Patients A national cohort of 122 124 patients who were elderly ( aged 65-84 years), receiving Medicare, and hospitalized with acute myocardial infarction ( AMI) in 1994-1995, and who were eligible for cardiac catheterization. Baseline chart reviews were taken from the Cooperative Cardiovascular Project and linked to Medicare health administrative data to provide a rich set of prognostic variables. Patients were followed up for 7 years through December 31, 2001, to assess the association between long-term survival and cardiac catheterization within 30 days of hospital admission.Main Outcome Measure Risk-adjusted relative mortality rate using each of the analytic methods.Results Patients who received cardiac catheterization (n = 73 238) were younger and had lower AMI severity than those who did not. After adjustment for prognostic factors by using standard statistical risk-adjustment methods, cardiac catheterization was associated with a 50% relative decrease in mortality ( for multivariable model risk adjustment: adjusted relative risk [RR], 0.51; 95% confidence interval [CI], 0.50-0.52; for propensity score risk adjustment: adjusted RR, 0.54; 95% CI, 0.53-0.55; and for propensity-based matching: adjusted RR, 0.54; 95% CI, 0.52-0.56). Using regional catheterization rate as an instrument, instrumental variable analysis showed a 16% relative decrease in mortality ( adjusted RR, 0.84; 95% CI, 0.79-0.90). The survival benefits of routine invasive care from randomized clinical trials are between 8% and 21%.Conclusions Estimates of the observational association of cardiac catheterization with long-term AMI mortality are highly sensitive to analytic method. All standard risk-adjustment methods have the same limitations regarding removal of unmeasured treatment selection biases. Compared with standard modeling, instrumental variable analysis may produce less biased estimates of treatment effects, but is more suited to answering policy questions than specific clinical questions.