Cystatin C based estimation of glomerular filtration rate and association with atherosclerosis imaging markers in people living with HIV

Abstract

Introduction: Reduced estimated glomerular filtration rate (eGFR) is associated with increased risk of cardiovascular disease among people living with HIV (PLWH). It is unclear whether eGFR equations incorporating Cystatin C (CysC) measurements are more predictive of preclinical CVD than those using only creatinine (Cr). Objectives: The study aimed to determine which of the three Chronic Kidney Disease Epidemiology (CKD-EPI) eGFR equations is most associated with carotid intima media thickness (CIMT) and coronary artery calcium (CAC) score. Methods: This cross-sectional analysis of pooled data from three large cohorts compared the associations between the three CKD-EPI eGFR equations (Cr, CysC, and Cr-CysC) with CIMT and CAC score using multivariable regression analysis. eGFR and CIMT were analyzed as continuous variables. CAC scores were analyzed as a binary variable (detectable calcification versus nondetectable) and as a log10 Agatston score in those with detectable CAC. Results: 1487 participants were included, and of these 910 (562 HIV+, 348 HIV-) had CIMT measurements and 366 (296 HIV+, 70 HIV-) had CAC measurements available. In HIV- participants, GFR estimated by any CKD-EPI equation did not significantly correlate with CIMT or CAC scores. When PLWH were analyzed separately including HIV-specific factors, only GFR estimated using Cr-Cys C correlated with CIMT [β= -0.90, 95% CI (-1.67,-0.13) μm; p=0.023]. Similarly, eGFR correlated with Agatston scores only when using cystatin C-based eGFR [β= -8.63, 95% CI (-16.49,-0.77) HU; p=0.034]. Associations between other eGFR formulas and CAC did not reach statistical significance. Conclusion: In PLWH, preclinical atherosclerosis may be more closely correlated with eGFR using formulae that incorporate CysC measurements than Cr alone.