Clinical Study Cystatin C as a Predictor of Mortality and Cardiovascular Events in a Population with Chronic Kidney Disease Ana Vigil, 1 Emilia Condés, 2 Luis Vigil, 3 Paloma Gallar, 1 Aniana Oliet, 1 Olimpia Ortega, 1 Isabel Rodriguez, 1 Milagros Ortiz, 1 Juan Carlos Herrero, 1 Carmen Mon, 1 Gabriela Cobo, 1 and Juana Jimenez 4 1 Department of Nephrology, Nephrology Service, Hospital Universitario Severo Ochoa, Avenida. Orellana s/n, Legan´ es, 28911 Madrid, Spain 2 Department of Medical Specialties, Psychology and Applied Pedagogy, Universidad European de Madrid, Villaviciosa de Odon, 28670 Madrid, Spain 3 Hypertension Unit, Department of Internal Medicine, Hospital Universitario de Mostoles, M´ ostoles, 28935 Madrid, Spain 4 Department of Biochemistry, Hospital Universitario Severo Ochoa, Leganes, 28911 Madrid, Spain Correspondence should be addressed to Ana Vigil; avigil@telefonica.net Received 20 September 2013; Revised 14 December 2013; Accepted 17 December 2013; Published 11 February 2014 Academic Editor: Greg Tesch Copyright © 2014 Ana Vigil et al. is is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Background. We examine whether cystatin C, a surrogate marker of renal function, could identify patients with chronic kidney disease (CKD) with an increased risk of renal disease progression, death, or cardiovascular events. Methods. Data were obtained for 180 patients, with a diagnosis of chronic renal failure based on serum creatinine estimated glomerular filtration rate (eGFR creat ) <90 mL/min/1.73 m 2 . is population was grouped in tertiles according to cystatin C and creatinine values at baseline. Cardiovascular events and overall mortality were estimated for each tertile. Predictors of overall mortality and for the development of renal disease progression were analyzed. Results. e median age was 75 years (interquartile range 69–82) and the median eGFR creat 38 mL/min m 2 (interquartile range 33–49). Overall mortality was lower on the first and on the second tertiles of cystatin C than on the third one (HR = 0.060; 95% CI: 0.008–0.447 and HR = 0.094; 95% CI: 0.022–0.406, resp.). Deaths related to the creatinine tertiles followed the same pattern, but differences were not as large. Cardiovascular mortality was lower on the second than on the third cystatin C tertile (HR = 0.198; 95% CI: 0.040–0.987), but it did not show differences on the first and the second creatinine tertiles compared with the third one (HR = 0.126; 95% CI: 0.013–1.265 and HR = 0.403; 95% CI: 0.093–1.740). e only independent predictors of mortality during followup were baseline cystatin C (OR = 0.100; 95% CI: 0.021–0.463) and baseline uric acid (OR = 1.377; 95% CI: 1.070–1.773). Conclusion. Cystatin C may be an alternative to creatinine for detecting a high risk of death and cardiovascular events in a population with CKD. 1. Introduction Chronic kidney disease is a worldwide health problem that carries a significant risk of cardiovascular morbidity and mortality. Endogenous filtration markers have been used as tests of kidney function, with serum creatinine as the most widely applied marker. Estimated glomerular filtration rate (eGFR) based on serum creatinine (eGFR creat ) does not fully account for non-GFR determinants of creatinine (muscle mass, race, age, and gender). An alternative endogenous serum biomarker, cystatin C, has been proposed for estimating renal function that can replace or supplement serum creatinine. In multiple studies it has been shown to be more sensitive for predicting adverse events than serum creatinine or eGFR creat . is parameter also showed greater sensitivity to detect mild reductions in renal function and improved the identification Hindawi Publishing Corporation International Journal of Nephrology Volume 2014, Article ID 127943, 7 pages http://dx.doi.org/10.1155/2014/127943