Predictive factors of progression of chronic renal insufficiency: a multivariate analysis

The purpose of this study was to identify clinical, nutritional, and laboratory factors associated with the rate of progression of chronic renal insufficiency among children and adolescents admitted to a pre-end-stage renal failure (ESRF) interdisciplinary program. Sixty-two children and adolescents aged 2 months to 19 years with chronic renal failure on conservative management were prospectively followed from 1990 to 1999. The following variables were analyzed: age at admission, sex, race, blood pressure, primary renal disease, Z scores for weight and height, glomerular filtration rate (GFR), urea, and presence and degree of proteinuria. Progression to ESRF was assigned as a dependent variable. The analysis was conducted in two steps. In a univariate analysis, variables associated with ESRF outcome were identified by the log-rank test. Then, the variables that were significantly associated with adverse outcome were included in a multivariate analysis. This analysis, using the Cox proportional hazards model, was performed to identify variables that were independently associated with a worse prognosis. Only variables that remained independently associated with adverse outcome were included in the final model. Twenty-one (34%) patients evolved to ESRF during a median follow-up of 43 months. Two variables were identified as independent predictors of progression to ESRF: GFR under 30 ml/min (RR=3, 95% CI=1.7-5.3, P=0.0001) and severe proteinuria (RR=3.1, 95% CI=1.2-7.6, P=0.01). The combination of two factors-GFR lower than 30 ml/min and presence of severe proteinuria on admission-was an independent indicator of adverse outcome in children and adolescents with chronic renal insufficiency who were conservatively managed.