FP183
Averange Creatinine-Urea Clearance: Revival of an Old Analytical Technique? Free

INTRODUCTION: Estimating kidney glomerular filtration rate (eGFR) is of utmost importance in many clinical conditions. In the World, the most common methods utilized to eGFR are equations based in plasma creatinine (PCr) such as the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI). However, rare studies have evaluated the performance of eGFR all degrees of impairment kidney with average of the urinary clearances creatinine-urea (CrUCl) and CKD-EPI

METHODS: The study included 4,784 measurements in 1,696 participants referred to the Renal and Metabolic Function Exploration Unit of Edouard Herriot Hospital (Lyon, France). GFR was measured by urinary inulin then estimated with IDMS-traceable CKD-EPI equation and CrUCl. The participants' ages ranged from 17 to 84 years and the measured GFRs from 5 to 191 mL/min/1.73 m2.

RESULTS: In the whole sample, the CrUCl performed better than CKD-EPI equation (precision: 10.0 [95% CI: 9.5; 10.0] vs. 16.0 [95% CI: 15.5; 16.5]), and accuracy: 96.5 [95% CI: 96.0; 97.0] vs. 79.5 [95% CI: 78.5; 81.0], P<0.001, respectively). In patients with GFR <30 mL/min/1.73 m2, the CrUCl  had the best  performance than CKD-EPI (bias: 1.0 [95% CI: 0.5; 1.0], IQR: 4.0 [95% CI:3.5; 5.0] and P30: 86.0 [95% CI: 85.0; 90.0] vs. 5.0 [95% CI: 4.0; 5.5], IQR: 10.0 [95% CI: 9.5; 11.5] and P30: 55.0 [95% CI: 50.0; 60.0], P< 0.001).

CONCLUSIONS: The results from this study suggest that CrUCl may be more reliable than CKD-EPI for estimating GFR in all categories of Chronic Kidney Disease.