Determinants of the Evolution of Kidney Function With Age

INTRODUCTION: Kidney function declines with age, but its determinants in the general population remain incompletely understood. We investigated the rate and determinants of kidney function decline in the general population. METHODS: Participants with information on kidney function were selected from a population-based cohort study. Joint models were used to investigate the evolution of the estimated glomerular filtration rate (eGFR, expressed in ml/min per 1.73 m(2) per year) and the urine albumin-to-creatinine ratio (ACR, expressed in mg/g per year) with age. We stratified for 8 potential determinants of kidney function decline, including sex, cardiovascular risk factors, and cardiovascular disease. RESULTS: We included 12,062 participants with 85,922 eGFR assessments (mean age 67.0 years, 58.7% women) and 3522 participants with 5995 ACR measurements. The annual eGFR decline was 0.82 and the ACR increase was 0.05. All determinants appeared detrimental for eGFR and ACR, except for prediabetes and higher body mass index which proved only detrimental for ACR. In participants without the determinants, eGFR decline was 0.75 and ACR increase was 0.002. Higher baseline eGFR but faster eGFR decline with age was detected in men (0.92 vs. 0.75), smokers (0.90 vs. 0.75), and participants with diabetes (1.07 vs. 0.78). CONCLUSION: We identify prediabetes, smoking, and blood pressure as modifiable risk factors for kidney function decline. As with diabetes, hyperfiltration seems important in accelerated kidney function decline in men and smokers. The interpretation of kidney function decline may require adjustment for age and sex to prevent overdiagnosis of chronic kidney disease in aging populations.