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

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.

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.

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.

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.