The effect of increasing age on the prognosis of non-dialysis patients with chronic kidney disease receiving stable nephrology care

To define whether age modifies the prognosis of patients with chronic kidney disease (CKD) on nephrology care, we prospectively followed patients with CKD who have been receiving nephrology care in a clinic for 1 year or more. The incidence of end-stage renal disease (ESRD), defined by the occurrence of dialysis or transplant, or death without ESRD was estimated by a competing-risk approach, and interactions between age and risk factors tested in Cox models over a median follow-up period of 62.4 months. Of 1248 patients with stage III-V CKD, 481 were younger than 65, 410 were between 65 and 75, and 357 were over 75 years old. Within each age class, the mean estimated glomerular filtration rate (eGFR) was 31, 32, and 29 ml/min per 1.73m(2), respectively. There were 394 ESRD events and 353 deaths. The risk of ESRD was higher than the risk of death without ESRD for ages <60 years, and independent of eGFR. The ESRD risk diminished with aging but still prevailed for eGFRs of 25-35 in patients between 65 and 75 years and with an eGFR below 15 in those up to 85 years old. Proteinuria significantly increased the risk of ESRD with advancing age. Surprisingly, the unfavorable effects of cardiovascular disease on ESRD and of diabetes on survival significantly decreased with increasing age. Male gender, higher phosphate, lower body mass index, and hemoglobin were age-independent predictors for ESRD, while cardiovascular disease, lower hemoglobin, higher proteinuria and uric acid, and ESRD also predicted death. Thus, in older patients on nephrology care, the risk of ESRD prevailed over mortality even when eGFR was not severely impaired. Proteinuria increases ESRD risk, while the predictive role of other modifiable risk factors was unchanged compared with younger patients. Kidney International (2012) 82, 482-488; doi:10.1038/ki.2012.174; published online 23 May 2012