Does cystatin C improve the precision of Cockcroft and Gaults creatinine clearance estimation?
GROUND: Cystatin C is increasingly used to estimate renal function, but its large intraindividual variability limits its practical value. This study aimed at verifying whether the clinical practice of associating cystatin C determination with serum creatinine (Cr) improved the ability of the Cockcroft and Gault formula to estimate creatinine clearance (CrCl). METHODS: It was an observational cross-sectional study of 134 in-patients with mildly impaired renal function. Using the Hoek et al formula (glomerular filtration rate (GFR)/1.73m2 = – 4.32 + 80.35/cystatin C mg/L), multivariate linear regressions (LREG) and artificial neural networks (ANN), we integrated cystatin C in the Cockcroft and Gault formula and analyzed the potential superiority of this procedure by comparing its performance with that of the two algorithms taken separately. RESULTS: The inclusion of cystatin C in the Cockcroft and Gault formula using the data of an LREG (CrCl = 0.371 x (Hoek et al) + 0.589 x Cockcroft an
