Abstract 16875: Cystatin C- versus Creatinine- Based Assessment of Renal Function in Patients Admitted With Heart Failure: Insights From DOSE, ROSE and CARRESS-HF

Abstract

Introduction: Serum creatinine (sCr) is routinely used to calculate estimated glomerular filtration rate (eGFR) in heart failure (HF) pts. However, changes in muscle mass may limit the accuracy of sCr as marker of renal function in this population. Cystatin C (CysC) is independent of muscle mass and provides an alternative measure of eGFR. In prior studies, higher sCr/CysC ratio has been associated with higher muscle mass. Herein, we compared CysC- and sCr-based eGFR at serial time points among pts admitted with HF. We hypothesized that muscle mass would decline during HF admission and this would result in a decrease of sCr/CysC ratio. Methods: We pooled pts from 3 trials performed in pts admitted with HF (DOSE, ROSE and CARRESS-HF). eGFR was calculated using CKD-EPI-CysC equation (eGFRCysC) and sCr-based MDRD equation (eGFRsCr). The relative difference between eGFRCysC and eGFRsCr (ΔeGFR) was calculated as follows: (eGFRCysC-eGFRsCr)/ eGFRsCr. To control for confounders, we analyzed changes in sCr/CysC ratio and in ΔeGFR among pts with samples available at both admission and a subsequent time point. Results: A total of 2849 samples were available in 841 pts (age 68 ± 13, 26% female, left ventricular ejection fraction 36 ± 17%). Compared with eGFRsCr, eGFRCysC reclassified 50% of the samples to different GFR categories, mainly to more advanced renal dysfunction (Fig. A). eGFRCysC was significantly lower than eGFRsCr at all time points (Fig. B). From time of admission to all subsequent time points, sCr/CysC ratio declined while ΔeGFR widened (all p-values<0.001). At time of enrollment in CARRESS-HF, each additional day of HF admission was associated with a decline in sCr/CysC ratio of 1.5% (p=0.04). Conclusions: The use of CysC reclassifies a large proportion of pts admitted with HF to more advanced renal dysfunction when compared to sCr-based assessment. The discrepancy between CysC- and sCr-based eGFR appears to widen during HF admission, likely due to muscle mass wasting.