BACKGROUND: The impact of heart failure (HF) etiology on prognosis of HF is not well known. METHODS: 3078 patients (median age 75years, 61% male) hospitalized with HF were studied. Patients were classified into six etiology groups: hypertension (HTN, 13.9%), ischemic heart disease (IHD, 42.4%), valvular disease (VHD, 9.5%), dilated cardiomyopathy (DCM, 7.9%), other (11.5%), and unknown etiology (14.8%). Patients with normal left ventricular ejection fraction (LVEF) were also included. Follow-up was up to 5years. RESULTS: In multivariable analysis, with HTN as the reference, VHD showed the highest risk, HR 1.71 (CI: 1.3-2.2, p/=30% (HR 1.3, CI: 1.0-1.5, p=0.03), compared to the reference (p-value for interaction