Background: Chronic kidney disease is a significant risk factor for end-stage kidney disease, cardiovascular events, and premature death. However, the prognostic value of low estimated glomerular filtration rate (eGFR) in the elderly is debatable.
Methods: We determined eGFR using the Japanese equation in 132,160 elderly subjects (65-75 years) who attended the special health checkup (Tokutei-Kenshin) in 2008 and investigated the association between baseline eGFR and 5-year all-cause and cardiovascular mortality.
Results: The median (SD) eGFR was 70.5 ± 15.3 mL/min/1.73 m2. During follow-up, we noted 2045 all-cause deaths including 408 from cardiovascular events. A J-shaped curve was obtained when all-cause and cardiovascular mortality rates were compared with decreases in eGFR, with the highest mortality observed for eGFR <45 mL/min/1.73 m2. These trends were statistically significant in the Kaplan-Meier analysis (P < 0.001). In the Cox proportional hazard analysis, after adjusting for possible confounders, those with eGFR <45 mL/min/1.73 m2, but not eGFR 45-59 mL/min/1.73 m2 showed a higher all-cause and cardiovascular mortality than those with eGFR >90 mL/min/1.73 m2 [hazard ratio (HR) 1.43, 95% confidence interval (CI) 1.06-1.91 for all-cause mortality, HR 2.28, 95% CI 1.28-4.03 for cardiovascular mortality]. Sex-based subgroup analyses showed similar results for both men and women.
Conclusions: We conclude that eGFR <45 mL/min/1.73 m2 is an independent risk factor for all-cause and cardiovascular mortality in the elderly population.
Keywords: Elderly; Glomerular filtration rate; Mortality.