background: kidney transplantation is the best alternative treatment for end-stage renal disease. several studies have been devoted to investigate predisposing factors of graft rejection. however, there is inconsistency between the results. the objective of the present study was to utilize an intuitive and robust approach for variable selection, random survival forests (rsf), and to identify im...

inflammatory basis in pathopoiesis of coronary artery disease (cad) have been demonstrated in recent decades. elevated c-reactive protein (crp) and leukocytosis were associated with an elevated risk   for acute coronary syndrome (acs). to evaluate the relationship between quantitative crp and cardiac troponin i in conjunction with white blood cell (wbc) count and 30 days outcomes and treatment ...

Lagged Duration Dependence in Mixed Proportional Hazard Models We study the non-parametric identification of a mixed proportional hazard model with lagged duration dependence when data provide multiple outcomes per individual or stratum. We show that the information conveyed by the within strata variation can be exploited to nonparametrically identify lagged duration dependence in more general ...

Persson, I. 2002. Essays on the Assumption of Proportional Hazards in Cox Regression. Acta Universitatis Upsaliensis. Comprehensive Summaries of Uppsala Dissertations from the Faculty of Social Sciences 110. 36 pp. Uppsala. ISBN 91-554-5208-6. This thesis consists of four papers about the assumption of proportional hazards for the Cox model in survival analysis. The first paper compares the haz...

Previously, we produced complete regression of allogeneic and syngeneic rat tumors by in situ tumor modification with a hapten, L-phenylalanine mustard (PhM), followed by i.v. admin istration of an antiserum developed against PhM-tumor extract conjugate. To evaluate the effect of this local treatment on untreated tumors, only one of two syngeneic methylcholanthrene-induced rat fibrosarcomas tra...

conclusions by controlling the modifiable risk factors and modality of treatment in our study, physicians can reach more effective treatment. results at the end of the study, long-term graft failure was seen in 27 (10.2%) cases. one-year and 2-year graft survival after diagnosis of cancer were 93.6% and 91.7%, respectively. the univariate analysis showed that the incidence of chronic graft loss...

Inflammatory bowel diseases (IBDs) are chronic and impose significant, multidimensional burdens on patients and health care systems. The increasing prevalence of IBD will only worsen this problem globally-population health management (PHM) strategies are needed to increase quality of care and population health outcomes while reducing health care costs. We discuss the key components of PHM in IB...

Survival bias is a potential problem when subjects are lost to follow-up, and this selection issue may arise in a wide range of biomedical studies. Controlling for the bias is difficult because subjects may be lost due to unmeasured factors. This article presents a two-step method that adjusts for survival bias in the proportional hazards model, even when unmeasured factors influence survival. ...

Recent clinical studies have demonstrated that high blood lactate in the prehospital setting and poor lactate clearance in the emergency department are predictive of in-hospital mortality. This analysis of data collected from a swine model of hemorrhage and restricted volume resuscitation investigated the hypotheses that noninvasive muscle pH (pHm) and H clearance would predict mortality, and t...

BACKGROUND Randomized Controlled Trials almost invariably utilize the hazard ratio calculated with a Cox proportional hazard model as a treatment efficacy measure. Despite the widespread adoption of HRs, these provide a limited understanding of the treatment effect and may even provide a biased estimate when the assumption of proportional hazards in the Cox model is not verified by the trial da...