比较QuantiFERON~-TB法与结核菌素皮肤试验检测潜伏结核感染的成本效益

目的:评估QuantiFERON~-TB(QFT)、结核菌素皮肤试验(TST)及两种方法联合(TST+QFT)检测在法国接种过卡介苗(BCG)人群结核潜伏感染(LTBI)的成本效益。方法:建立决策分析模型评估结核(TB)密切接触成人三种检测方案的效果,并计算直接医疗成本,预期寿命和增量费用-效果比率(incremental cost-effectiveness ratios,ICERs)。结果:每位病人在无检测、TST检测、QFT检测和TST+QFT检测时兑现直接医疗费用分别为417欧元、476欧元、443欧元、435欧元,而兑现预期寿命分别为25.030、25.071、5.073和25.062年。相比QFT,TST的成本较高、效率低;与未检测相比,TST+QFT检测与获得每个生命年(year of life gained,YLG)需560欧元的一个ICER有关。与TST+QFT相比,QFT检测与获得每个生命年需730欧元的一个ICER有关。只有在LTBI率低(<5%)和TST特异性高(>90%)的情况下,QFT与ICER>75 000欧元/YLG有关。结论:在法国,各种诊断结核病密切接触者LTBI的方法中...

Comparison of Cox Model Methods in A Low-dimensional Setting with Few Events

Prognostic models based on survival data frequently make use of the Cox proportional hazards model. Developing reliable Cox models with few events relative to the number of predictors can be challenging, even in low-dimensional datasets, with a much larger number of observations than variables. In such a setting we examined the performance of methods used to estimate a Cox model, including （i） full model using all available predictors and estimated by standard techniques, （ii） backward elimination （BE）, （iii） ridge regression, （iv） least absolute shrinkage and selection operator （lasso）, and （v） elastic net. Based on a prospective cohort of patients with manifest coronary artery disease （CAD）, we performed a simulation study to compare the predictive accuracy, calibration, and discrimination of these approaches, Candidate predictors for incident cardiovascular events we used included clinical variables, biomarkers, and a selection of genetic variants associated with CAD. The penalized methods, i.e., ridge, lasso, and elastic net, showed a comparable performance, in terms of predictive accuracy, calibration, and discrimination, and outperformed BE and the full model. Excessive shrinkage was observed in some cases for the penalized methods, mostly on the simulation scenarios having the lowest ratio of a number of events to the number of variables. We conclude that in similar settings, these three penalized methods can be used interchangeably. The full model and backward elimination are not recommended in rare event scenarios.