Nonprogressive kidney dysfunction and outcomes in older adults with chronic kidney disease

Abstract

Objectives: To determine whether a subgroup of patients with severe but nonprogressive renal dysfunction exist and to characterize this subgroup.

Design: Retrospective longitudinal monocentric cohort study.

Setting: Nephrology clinic for chronic kidney disease (CKD).

Participants: Between January 1998 and December 2004, 177 consecutive patients aged 80 and older were referred for the first time to nephrology for CKD.

Measurements: The characteristics of patients with nonprogressive or progressive CKD (estimated glomerular filtration rate (eGFR) decline of < and > or =1 mL/min per 1.73 m(2) per year, respectively) were observed and analyzed, and their risk of dying or requiring dialysis was determined. After exclusion of subjects requiring immediate dialysis or followed up for less than 6 months, 138 patients remained eligible for analysis.

Results: In the study cohort (initial mean eGFR 31.8 mL/min per 1.73 m(2), median follow-up 47 months), patients were more likely to require dialysis than to die; 36% of patients had nonprogressive CKD. This characteristic, predicted by low proteinuria, lack of hypertension, and low cardiovascular comorbidity, was the strongest predictor of global survival. In progressors, two independent covariates (eGFR <30 mL/min per 1.73 m(2) and hemoglobin < or =11 g/dL at inclusion) predicted the risk of requiring dialysis.

Conclusion: More than one-third of subjects aged 80 and older referred to a nephrology center had severe but nonprogressive kidney dysfunction. This subgroup had a lower mortality rate than those with progressive kidney dysfunction. Simple covariates (low proteinuria, lack of hypertension, low cardiovascular comorbidity) predicted nonprogression of CKD. Distant nephrology follow-up of such patients may be sufficient.