Glomerular filtration rate: new age- and gender- specific reference ranges and thresholds for living kidney donation

Abstract

BACKGROUND: There is a need for a large, contemporary, multi-centre series of measured glomerular filtration rates (mGFR) from healthy individuals to determine age- and gender-specific reference ranges for GFR. We aimed to address this and to use the ranges to provide age- and gender-specific advisory GFR thresholds considered acceptable for living kidney donation. METHODS: Individual-level data including pre-donation mGFR from 2974 prospective living kidney donors from 18 UK renal centres performed between 2003 and 2015 were amalgamated. Age- and gender-specific GFR reference ranges were determined by segmented multiple linear regression and presented as means ± two standard deviations. RESULTS: Males had a higher GFR than females (92.0 vs 88.1 mL/min/1.73m2, P < 0.0001). Mean mGFR was 100 mL/min/1.73m2 until 35 years of age, following which there was a linear decline that was faster in females compared to males (7.7 vs 6.6 mL/min/1.73m2/decade, P = 0.013); 10.5% of individuals aged > 60 years had a GFR < 60 mL/min/1.73m2. The GFR ranges were used along with other published evidence to provide advisory age- and gender-specific GFR thresholds for living kidney donation. CONCLUSIONS: These data suggest that GFR declines after 35 years of age, and the decline is faster in females. A significant proportion of the healthy population over 60 years of age have a GFR < 60 mL/min/1.73m2 which may have implications for the definition of chronic kidney disease. Age and gender differences in normal GFR can be used to determine advisory GFR thresholds for living kidney donation.