Cystatin C-Based eGFR Is a Superior Prognostic Parameter to Creatinine-Based eGFR in Post-Endovascular Therapy Peripheral Artery Disease Patients

Background: Kidney dysfunction is reportedly associated with adverse outcome in patients with peripheral artery disease (PAD). Estimated glomerular filtration rate (eGFR), a recently popularized index for assessing kidney function, is calculated using serum creatinine or cystatin C. Compared with creatinine-based eGFR (eGFRcr), cystatin C-based eGFR (eGFRcys) is less affected by age, gender, and muscle mass. We hypothesized that eGFRcys is a feasible prognostic biomarker despite muscle sarcopenia in patients with PAD. Methods and Results: We calculated both eGFRcr and eGFRcys according to the Kidney Disease: Improving Global Outcomes (KDIGO) guideline in 234 PAD patients who underwent endovascular therapy. Patients were prospectively followed during a median follow-up period of 964 days for the endpoint of major adverse cardiovascular and cerebrovascular events (MACCE). On multivariate Cox proportional hazard analysis eGFRcys, but not eGFRcr, was an independent predictor of MACCE. The C index was larger for eGFRcys than eGFRcr (0.69 vs. 0.57, P=0.0006). On Kaplan-Meier analysis the incidence of MACCE was increased with advancing chronic kidney disease stage based on eGFRcys, but not on eGFRcr, in patients with PAD. Net reclassification index was improved with the addition of eGFRcys to basic predictors. Conclusions: Compared with eGFRcr, eGFRcys may be a more reliable biomarker for MACCE and patient risk stratification.