Avaliação da média das depurações de creatinina e ureia para estimar a taxa de filtração glomerular

Abstract

Chronic kidney disease is defined as changes in kidney function or structure for three months or more. Glomerular filtration rate (GFR) is the main indicator to assess kidney function. Markers considered as gold standard for GFR measurement, such as inulin, are invasive, expensive, and not recommended in routine analyses. Equations based on endogenous substances, like creatinine, are used and recommended to estimate GFR, but they may be inaccurate in more advanced stages of kidney disease. Estimated GFR in patients with advanced kidney disease can be obtained by calculating average creatinine-urea clearance (CrUCl); however, few studies assessing its performance have been described. In this context, the present work aimed to evaluate the performance of average CrUCl to estimate GFR. This cross-sectional study conducted at hospital Edouard Herriot (Lyon, France) considered a French population of 855 participants with suspected or confirmed kidney dysfunction after kidney transplantation or candidates for kidney donation who performed a GFR measurement by urinary inulin clearance. The performance of CrUCl was compared with that of CKD-EPI 2009 and CKD-EPI 2021 equations considering three criteria: bias, precision, and accuracy. Participant's mean age (±SD) was 47.4 ± 14.4 years, and GFR ranged from 10 to 168 mL/min/1.73 m2. In the whole sample, CrUCl performed similarly to CKD-EPI equations (2009 and 2021) (precision: 11.5 [95% CI: 10.5; 12.5] vs. 19.0 [95% CI: 17.2; 20.1] and 19.1 [95% CI:17.4; 20.4]; and accuracy P30: 97.0 [95% CI: 95.8; 98.0] vs. 82.0 [95% CI: 79,2; 84,4] and 77.2 [95% CI: 74.5; 80.0]). The CKD-EPI equations (2009 and 2021) had the best performance when mGFR > 60 mL/min/1.73m2. In contrast, CrUCl performed better than others with lowest GFR values, especially when mGFR < 60 mL/min/1.73m2. This study described the best performance of CrUCl at GFR levels <60 mL/min/1.73m2 and a satisfactory result in the assessed population. [resumo fornecido pelo autor]