Competing risk factor analysis of end-stage renal disease and mortality in chronic kidney disease

Background: Death and dialysis are competing outcomes in patients with chronic kidney disease (CKD). The factors associated with end-stage renal disease (ESRD) versus death in this population are unknown. The purpose of our study was to evaluate the competing risk of ESRD versus mortality and to evaluate the risk factors associated with these two outcomes.

Methods: We prospectively recruited 220 consecutive patients at a Veterans Administration Medical Center attending a renal clinic who met the definition of CKD (estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m(2) or urine protein/creatinine ratio of >0.22 g/g). Using age, race, proteinuria, eGFR, systolic blood pressure, and coronary artery disease as predictors, we calculated the competing end-points of ESRD or death using a competing Cox regression model.

Results: The cumulative incidence for ESRD was 17.6% and death 18.5% during follow-up that lasted up to 7 years. ESRD was predicted by younger age (hazard ratio (HR) 0.91/year), black race (HR 2.75), higher systolic blood pressure (HR 1.02/mm Hg), proteinuria (HR 1.37/log urine protein/creatinine ratio) and low eGFR (0.014/log eGFR ml/min/1.73 m(2)). Death was predicted by older age (HR 1.07/year), lower eGFR (HR 0.43/log eGFR ml/min/1.73 m(2)), proteinuria (HR 1.26/log urine protein/creatinine ratio) and coronary artery disease (HR 2.52). The coefficients were statistically different for age (p < 0.001), log eGFR (p < 0.001) and systolic blood pressure (p = 0.04) for ESRD and death outcomes.

Conclusions: The risk for mortality is similar to the risk of ESRD in the CKD population of veterans seen by nephrologists. Risk factors for ESRD and death appear to differ in this population. Certain clinical and demographic factors may discriminate between the end-points of death or dialysis and may influence decisions about planning for ESRD.