[Inadequacy of the African-American ethnic factor to estimate glomerular filtration rate in an African general population: Results from Côte d'Ivoire].

Glomerular filtration rate (GFR) estimation is fundamental in clinical nephrology. It is usually estimated from equations based on serum creatinine. An ethnic factor is currently recommended for the black population for the two most used equations, i.e. the Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) and Modification of Diet in Renal Disease (MDRD) study equations. However, these factors were determined from African-American subjects. Therefore, their use in the African subject (non-American) remained questionable. To date, no data are available in West Africa for the adequacy of these ethnic coefficients, as compared with a measurement of GFR by a reference method. One hundred and twenty subjects of the general population, with no nephrologic history, were included in the study (60 women and 60 men). GFR was determined by a reference method, i.e. the plasma clearance of iohexol. The performance (bias, standard deviation, accuracy within 30%) of both CKD-EPI and MDRD study equations were assessed with and without the ethnic factors. GFR measurements (mGFR) according iohexol reference method were 100±19mL/min/1.73m2. The MDRD study equation without any ethnic factor underestimates mGFR by -9±16mL/min/1.73m2, whereas the MDRD study equation with the ethnic factor overestimates mGFR by +10±18mL/min/1.73m2. Regarding the CKD-EPI equation, bias and accuracy within 30% are significantly better without than with the ethnic factor. Indeed, bias is 16±2mL/min/1.73m2 and 18±17mL/min/1.73m2 and accuracy is 93% and 76%, without and with the ethnic factor, respectively (P<0.0001). We show for the first time in African population that the performance of CKD-EPI and MDRD study equations is significantly better, in a general population, without the "African-American" ethnic factor. The "African-American" ethnic factor should not be applied in West Africa.