New Argentine Equation to estimate the Glomerular Filtration Rate

Pennsylvania

Congreso; ASN Kidney Week 2023; 2023

American Society of Nephrology

BackgroundLatin Americans are poorly represented in the current glomerular filtration rate equations(eGFR), so their predictions are difficult to extrapolate in our population.Objetive: to develop a new equation to estimate GFR based on data from Argentina and compareits performance with those currently available.MethodsCross-sectional study. We included all adults whose GFR was measured with urinary clearanceof iothalamate (mGFR) between 2007 and 2017 (development sample?DS-, n=583). The chosenequation was based on a quasi-likelihood model with identity variance function and logarithmiclink to predict mGFR from the square root of creatinine, age, sex, monoren, albumin and thelogarithm of urea. Later, an independent sample was added between 2018 and 2019 (temporary validation sample -TVS-, n=78). The performance of the new equation was compared with theprevious ones (MCQ, MDRD 4 and 6, CKD-EPI 2009 and 2021) in the DS (by 10-fold crossvalidation)and in the TVS.ResultsThere were no differences in the baseline characteristics in both samples and they presented awide range in the mGFR (1.9-186.6 ml/min/1.73 m2).Within the previous equations, CKD-EPI (2009 and 2021) obtained the best performance(comparator).In the DS, Argentine Equation (AE) presented a lower RMSE, higher P15, bias median closer tozero, and a higher %CC compared to CKD-EPI 2009. In addition, from Q1, M, and Q3 of thebias, a greater shift to the left of CKD-EPI 2009. Compared with CKD-EPI 2021, AE obtained amedian bias closer to 0, and in the rest of the metrics it was slightly lower, although very similar(table 1).In the TVS, AE presented a lower RMSE, higher r, P30 and %CC compared to CKD-EPI in itstwo versions. In addition, it presented a median bias closer to 0 and a higher P15 compared toCKD-EPI 2009.ConclusionAE presented a better global performance to estimate GFR in residents of Argentina compared tothe currently equations.