倾向性评分与疾病风险评分匹配对已测量混杂因素的控制效果评价

Evaluation of the control effect for measured confounders between propensity score matching and disease risk score matching

目的比较在组间倾向性评分(propensity score,PS)重叠较好和较差的场景下应用PS和疾病风险评分(disease risk score,DRS)进行1∶1匹配的效果,同时探索DRS匹配的最优卡钳值。方法设置不同的试验组样本量占比、结局事件发生率和PS重叠情况,模拟6种场景比较PS和DRS匹配前后的协变量均衡性和处理效应估计偏差,并进行实例分析。结果PS重叠较好的场景下,DRS重叠也较好,PS匹配优于DRS,PS匹配最优卡钳值为标准差的10%~20%,DRS匹配相对最优卡钳值为标准差的0.5%。在PS重叠较差的场景中,DRS重叠也变差,但DRS匹配优于PS,DRS匹配最优卡钳值为标准差的15%~20%。此外,PS和DRS匹配对协变量均衡性的改善效果与处理效应估计偏差相一致。结论当PS重叠较好时,优选PS匹配;当PS重叠较差时,可选DRS,其最优卡钳值为标准差的15%~20%。在实际应用中,可根据匹配前后组间协变量均衡性指标的改善情况评价匹配效果。

Objective To compare propensity score(PS)matching and disease risk score(DRS)matching in the scenarios of good PS overlap and poor PS overlap,and to investigate the optimal caliper width for DRS matching.Methods According to the different proportions of the test group and events as well as the different PS overlap situations,6 scenarios were simulated to compare the balance of covariables and the bias before and after PS matching or DRS matching,followed by analysis of an actual case.Results In the scenarios with good PS overlap,the DRS overlap was also good,and PS matching was more accurate than DRS matching.The optimal caliper width was found to be 10%-20%of the PS standard deviation(SD)for PS matching,and the relative optimal caliper width was 0.5%of the DRS SD for DRS matching.In the scenarios with poor PS overlap,the DRS overlap was also poor,but the DRS matching was more accurate than PS matching.The optimal caliper width was found to be 15%-20%of the DRS SD.In addition,the improvement on the balance of covariates was consistent with the estimation bias of treatment effect.Conclusions When the overlap of PS is good,PS matching is preferred;when the overlap of PS is poor,DRS matching can be selected,and the optimal caliper width is 15%-20%of the DRS SD.In practical application,the control effect for measured a confounder can be evaluated according to the improvement on the covariable balance between groups.