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  1. Modeling mortality risk in hemodialysis patients using laboratory values as time-dependent covariates.

    Article - En anglais

    Proportional hazards analyses assume that the magnitude of mortality risk for a predictor variable remains proportional over time.

    In a time-dependent model, the explanatory variable violates this assumption, and repeat observations are required to accommodate the change in risk that occurs over time.

    Using a retrospective cohort design, we tested the following laboratory values for a time-by-covariate interaction : hematocrit (HCT), serum albumin (ALB), and serum creatinine (CR).

    A random sample of 4,083 hemodialysis patients whose specimens were analyzed in a central laboratory over a 3-year period served as the study group.

    Using the baseline observation, we discovered significant probability values for the interaction terms TIME*CR (P=0.013) and TIME*ALB (P<0.01).

    The beta coefficient for TIME*HCT was not significant, indicating that the proportional hazard assumption was not violated by this covariate.

    Based on these results, we fitted a multivariate regression model containing two time-dependent covariates (CR and ALB) using a data structure that incorporated repeat observations of these laboratory values.

    Patients with high ALB levels experienced the lowest mortality risk.

    Similarly, serum CR levels were higher in long-term survivors.

    This analysis verifies the clinical importance of monitoring ALB and CR levels over time and the hazard of using a single laboratory observation to make long-term projections. (...)

    Mots-clés Pascal : Hémodialyse, Evaluation, Facteur risque, Mortalité, Modélisation, Hématocrite, Albumine, Créatinine, Sérum, Etude statistique, Homme, Epuration extrarénale, Appareil urinaire pathologie, Rein pathologie, Insuffisance rénale

    Mots-clés Pascal anglais : Hemodialysis, Evaluation, Risk factor, Mortality, Modeling, Hematocrite, Albumin, Creatinine, Serum, Statistical study, Human, Extrarenal dialysis, Urinary system disease, Kidney disease, Renal failure

    Logo du centre Notice produite par :
    Inist-CNRS - Institut de l'Information Scientifique et Technique

    Cote : 97-0033947

    Code Inist : 002B27B03. Création : 21/05/1997.