Cystatin C in Acute Heart Failure Without Advanced Renal Impairment

BACKGROUND: The prognostic value of cystatin C relative to glomerular filtration rate (GFR) estimated by the Modification of Diet in Renal Disease Study (MDRD) equation modified for Japan has not been investigated in acute heart failure patients with normal to moderately impaired renal function. More accurate detection of mild renal impairment might improve the risk stratification of heart failure patients, especially patients with normal to moderately impaired renal function. METHODS: Cystatin C and creatinine levels were measured on admission in 328 consecutive patients hospitalized for worsening chronic heart failure with a GFR estimated by MDRD equation modified for Japan >= 30 mL/min/1.73 m(2). RESULTS: During a median follow-up period of 915 days, there were 52 (16%) cardiac deaths. In stepwise Cox regression analyses including cystatin C and GFR estimated by MDRD equation modified for Japan (either as continuous variables or as variables categorized into quartiles), cystatin C (P <.0001), but not GFR estimated by MDRD equation modified for Japan, was independently associated with cardiac mortality. Adjusted relative risk according to the quartiles of these markers and Kaplan-Meier analyses revealed that the cystatin C was a better marker to separate low-risk from high-risk patients. Furthermore, receiver-operating characteristic curve analyses of these markers revealed that cystatin C showed a higher precision in predicting cardiac mortality. CONCLUSION: Measurements of cystatin C might improve early risk stratification compared with GFR estimated by MDRD equation modified for Japan in acute heart failure patients with normal to moderately impaired renal function. (C) 2009 Elsevier Inc. All rights reserved. (C) The American Journal of Medicine (2009) 122, 566-573