Frailty and the risk of kidney function decline in the elderly population: the Rugao Longevity and Ageing Study

Background. The diverse risk factors for kidney impairments suggest that kidney function decline is more likely to occur in individuals with a broadly constituted health deficit. Here we conducted a longitudinal cohort study to evaluate the association of baseline frailty status with the risk of estimated glomerular filtration rate (eGFR) decline. Methods. Overall, 1269 participants aged 70-84 years from Rugao Longevity and Ageing cohort with 3-year follow-up were included. Frailty was measured using a modified Fried frailty assessment. GFR was estimated using the Chronic Kidney Disease Epidemiology Collaboration equation. Associations between baseline frailty status and rapid eGFR decline were examined by multinomial logistic analysis. A linear mixed-effect model was used to determine eGFR decline in mL/min/1.73 m(2) over the study period comparing those with frail or prefrail at baseline versus those with robust status. Results. The mean (+/- standard deviation) age of participants was 75.1 +/- 3.8 years. A total of 144 (11%) participants had rapid eGFR decline by at least 10% during the 3-year follow-up. Compared with robust status, baseline frail status was associated with a 2.48-fold [95% confidence interval (CI) 1.24-4.95] increased risk of rapid eGFR decline after multiple adjustments. In multivariate linear mixed model analysis, subjects with frail status but not prefrail status at baseline had a significant coefficient of -1.70 (95% CI -3.35 to -0.04) for the frail x visit term, which indicates an accelerated eGFR decline compared with robust subjects over the study period (P = 0.044). Conclusions. Frailty may serve as an independent biomarker to predict the decline of kidney function.