GFR in healthy aging: An individual participant data meta-analysis of iohexol clearance in european population-based cohorts

Abstract

<i>Background</i> - Population mean GFR is lower in older age, but it is unknown whether healthy aging is associated with preserved rather than lower GFR in some individuals.<br><br>

<i>Methods</i> - We investigated the cross-sectional association between measured GFR, age, and health in persons aged 50–97 years in the general population through a meta-analysis of iohexol clearance measurements in three large European population-based cohorts. We defined a healthy person as having no major chronic disease or risk factors for CKD and all others as unhealthy. We used a generalized additive model to study GFR distribution by age according to health status.<br><br>

<i>Results</i> - There were 935 (22%) GFR measurements in persons who were healthy and 3274 (78%) in persons who were unhealthy. The mean GFR was lower in older age by −0.72 ml/min per 1.73 m2 per year (95% confidence interval [95% CI], −0.96 to −0.48) for men who were healthy versus −1.03 ml/min per 1.73 m2 per year (95% CI, −1.25 to −0.80) for men who were unhealthy, and by −0.92 ml/min per 1.73 m2 per year (95% CI, −1.14 to −0.70) for women who were healthy versus −1.22 ml/min per 1.73 m2 per year (95% CI, −1.43 to −1.02) for women who were unhealthy. For healthy and unhealthy people of both sexes, both the 97.5th and 2.5th GFR percentiles exhibited a negative linear association with age.<br><br>

<i>Conclusions</i> - Healthy aging is associated with a higher mean GFR compared with unhealthy aging. However, both the mean and 97.5 percentiles of the GFR distribution are lower in older persons who are healthy than in middle-aged persons who are healthy. This suggests that healthy aging is not associated with preserved GFR in old age.