Predictors of rapid progression of glomerular and nonglomerular kidney disease in children and adolescents: The chronic kidney disease in children (CKiD) cohort

Background Few studies have prospectively evaluated the progression of chronic kidney disease (CKD) in children and adolescents, as well as factors associated with progression. Study Design Prospective multicenter observational cohort study. Setting & Participants 496 children and adolescents with CKD enrolled in the Chronic Kidney Disease in Children (CKiD) Study. Predictors Proteinuria, hypoalbuminemia, blood pressure, dyslipidemia, and anemia. Outcomes Parametric failure-time models were used to characterize adjusted associations between baseline levels and changes in predictors and time to a composite event of renal replacement therapy or 50% decline in glomerular filtration rate (GFR). Results 398 patients had nonglomerular disease and 98 had glomerular disease; of these, 29% and 41%, respectively, progressed to the composite event after median follow-ups of 5.2 and 3.7 years, respectively. Demographic and clinical characteristics and outcomes differed substantially according to the underlying diagnosis; hence, risk factors for progression were assessed in stratified analyses, and formal interactions by diagnosis were performed. Among patients with nonglomerular disease and after adjusting for baseline GFR, times to the composite event were significantly shorter with urinary protein-creatinine ratio > 2 mg/mg, hypoalbuminemia, elevated blood pressure, dyslipidemia, male sex, and anemia, by 79%, 69%, 38%, 40%, 38%, and 45%, respectively. Among patients with glomerular disease, urinary protein-creatinine ratio >2 mg/mg, hypoalbuminemia, and elevated blood pressure were associated with significantly reduced times to the composite event by 94%, 71%, and 67%, respectively. Variables expressing change in patient clinical status over the initial year of the study contributed significantly to the model, which was cross-validated internally. Limitations Small number of events in glomerular patients and use of internal cross-validation. Conclusions Characterization and modeling of risk factors for CKD progression can be used to predict the extent to which these factors, either alone or in combination, would shorten the time to renal replacement therapy or 50% decline in GFR in children with CKD.