High total cholesterol is associated with lower mortality in dialysis patients, but the relationship between lipid levels and mortality in patients who have chronic kidney disease (CKD) and are not yet on dialysis is poorly described. This study examined the association between lipid levels and all-cause and cardiovascular mortality in 986 male patients (age 67.4 +/- 10.9 yr; race 23.7% black) ...

We examine a new general class of hazard rate models for duration data, containing parametric and nonparametric component. Both can be mix time effect possibly time-dependent covariate effects. A number well-known are special cases. In counting process framework, profile likelihood estimator is developed the component model shown to asymptotically normal efficient. Finite sample properties inve...

We consider the problem of clustering grouped and functional data, which are indexed by a covariate, and assessing the dependency of the clustered groups on the covariate. We assume that each observation within a group is a draw from a mixture model. The mixture components and the number of such components can change with the covariate, and are assumed to be unknown a priori. In addition to lea...

Longitudinal studies testing the relationship between repeated measures of vitamin D or fibroblast growth factor 23 (FGF23) and infectious and cardiac hospitalizations and death in hemodialysis patients have not been reported. We examined the association between yearly 25-hydroxyvitamin D (25(OH)D), 1,25-dihydroxyvitamin D (1,25(OH)2D), and FGF23 serum levels and various clinical outcomes using...

We consider the conditional randomization test as a way to account for covariate imbalance in randomized experiments. The test accounts for covariate imbalance by comparing the observed test statistic to the null distribution of the test statistic conditional on the observed covariate imbalance. We prove that the conditional randomization test has the correct significance level and introduce or...