New CAPA-dependent Cystatin C Equation: increased detection of decreased glomerular filtration in HIV-infected patients

Abstract

Introduction: Creatinine and its equations have clear limitations regarding their low sensitivity to identify initial stages of renal dysfunction. Cystatin C has been proposed as a promising marker, but so far, there has been no evidence showing the superiority of its equations over the creatinine ones. However, there are no studies which compare the performance of the latest cystatin equation developed by Grubb and collaborators in 2014: the “CAPA” equation. Objectives: To analyze the performance of CAPA equation to detect early reduction of glomerular filtration in HIV-infected patients, in comparison with creatinine-dependent equations: Cockroft-Gault, MDRD-4, CKD-EPI and MCQ. Methods: An analytical, observational, cross-sectional study was conducted between July and November 2017, at an Argentinian specialty hospital. ≥18-year old HIV-infected patients undergoing antiretroviral therapy were included. Cases with creatinine ≥1.2 mg/dL were excluded. Results: 100 patients were recruited, and 89 were included: 47 (52.8%) were women. CAPA equation detected more pronounced decreases in GFR than the creatinine-dependent equations. The mean values of GFR obtained by CAPA showed differences with the ones found through Cockroft-Gault (p <0.0001); MDRD-4 (p = 0.005); CKD-EPI (p <0.0001) and MCQ (p <0.0001). Of the 46 cases (51.7%) with GFR <90 ml/min detected through the use of any equation, CAPA detected 82.6% vs. 71.7% detected by the four creatinine formulas together (p <0.0001) and by each creatinine equation individually: CAPA vs. Cockroft-Gault (p = 0.01); vs. MDRD-4 (p <0.0001); vs. CKD-EPI (p = 0.005). Conclusions: CAPA equation detected more marked decreases in GFR than the creatinine-dependent equations in HIV-infected patients.

Keywords

• creatinina
• cistatina c
• daño renal
• medición del filtrado glomerular
• VIH