Glomerular filtration rates in healthy Asians without kidney disease

Abstract

Aim The Chronic Kidney Disease Collaboration - Epidemiology (CKD-EPI) glomerular filtration rates (GFR) estimation equation is believed to estimate GFR more accurately in healthy people but this has not been validated in Asians. We studied the distribution of GFR in a multi-ethnic Asian population without CKD, and compared the performance of measures of GFR estimation, including the CKD-EPI equation, Cockroft-Gault equation, and 24-hour urine creatinine clearances. Materials and Methods A total of 103 healthy volunteers without a history of kidney disease, hypertension, or diabetes underwent GFR measurement using 3-sample plasma clearance of 99mTc-DTPA. Cockroft-Gault estimated GFR and 24-hour urine creatinine clearances were normalized to body surface area. Results The mean measured GFR was 101 ± 15.8 mL/min per 1.73 m2 and was lowest in Indians (93 ± 12.3 mL/min per 1.73 m2; P < 0.001). The CKD-EPI equation appears to be more accurate for healthy participants. Estimated GFR correlated with measured GFR (r = 0.57, P < 0.001), and the mean difference is 3.72 ± 14.43 mL/min per 1.73 m2 (P < 0.001). However, estimating GFR using self-directed 24-hour urine creatinine clearances is poorer than using the CKD-EPI equation. Conclusions GFR estimation using self-directed 24-hour urine collection for creatinine clearance is less accurate than using the CKD-EPI equation. A larger study is required to clarify GFR in healthy Asians, and the association of health outcomes of Asian kidney donors with lower GFR thresholds. Summary at a Glance The applicability of GFR estimating equations in differing racial groups is key. In this paper, comparisons of estimated and measured eGFR are presented among people in Singapore of Chinese and Indian extraction. © 2013 Asian Pacific Society of Nephrology.