Two types of models were applied—a linear and nonlinear model with restricted cubic splines—to assess the U-shaped association. Statistical significance (set at 0.05) for the nonlinearity was tested by comparing the spline and linear models. Among the participants, 701 were certified as needing ...
Two types of models were applied—a linear and nonlinear model with restricted cubic splines—to assess the U-shaped association. Statistical significance (set at 0.05) for the nonlinearity was tested by comparing the spline and linear models. Among the participants, 701 were certified as needing ...
We applied three flexible nonparametric smoothing techniques for nonlinear covariate effect in the Cox models: penalized splines, restricted cubic splines and natural splines. Akaike information criterion (AIC) and degrees of freedom were used to smoothing parameter selection in penalized splines model. ...
A prognostic model should not enter clinical practice unless it has been demonstrated that it performs a useful role. External validation denotes evaluation of model performance in a sample independent of that used to develop the model. Unlike for logistic regression models, external validation of Co...
The impact of HbA1c on the presence of coronary artery disease (CAD), myocardial infarction (MI), and the severity of coronary lesions was explored through the use of restricted cubic splines. In a study of patients without diabetes, a statistically significant relationship was observed between ...
method can be used to pool the significance of categorical variables (multiparameter test). The model can contain continuous, dichotomous, categorical and restricted cubic spline predictors and interaction terms between all these type of variables. Variables can also be forced in the model during ...
The restricted cubic spline as baseline hazard in the proportional hazards model with step function time-dependent covariables. We incorporate a cubic spline function where the tails are linearly constrained, as the baseline hazard, into the proportional hazards model. We show estim... II James,FE...
the use of restricted cubic spline functions as alternatives to the linear functions of log time used in standard models. The authors demonstrate fitting these models and graphing predicted hazards, cumulative hazards, and survival functions with real data from breast cancer and prostate cancer studies...
2. METHODS In this analytical study to determine the nonlinear effects of covariate three non-parametric methods Penalize spline, restricted cubic spline and natural spline in Cox model were used. The ability of nonparametric methods was evaluated to recover the true functional form of linear, ...
若研究者进一步考察 主效应变量与结局间的剂量-反应关系或者考察二者 是否有线性趋势,可采用限制/ 自然三次样条Cox 回归 (restricted / natural cubic spline Cox's regression) 〔1 - 2〕 。 原理与方法 样条函数的目的是用几个定义在时间 t 范围子区 间上的低阶多项式(样条)代替定义在整个时间t 范围 上的...