Purpose: Although angiotensin-converting enzyme(ACE)in-hibitors are recommen ded for all patients with systolic heart failure, prior studies suggest that eld erly cohorts are less likely to receive such therapy. The purpose of this study was to determine the age dependence of adherence to guideline-based medical car e in hospitalized heart failure patients. Methods: We performed a multicenter ob servational cohort study including 613 patients admitted to participating hospit als with a primary diagnosis of heart failure with ejection fraction ≤40%. Thi s cohort was divided into four age groups(group 1:< 60, group 2:60-69, group 3: 70-79, and group 4:80 years) and adherence to guideline-based medical care was measured. Results: ACE inhibitors were administered to 83%of ideal heart failu re patients, and this rate was similar for all age groups. Elderly patients rece ived significantly lower ACE inhibitor dosages compared to their younger counter parts(168, 148, 125 and 117 mg captopril in groups 1, 2, 3, and 4, respectively, p=0.001). Lower creatinine clearance(p< 0.001), prior residence in a long-term care facility(p=0.037), intolerance to ACE inhibitors (p=0.006), lower blood pr essure(p=0.005), absence of a history of hypertension(p=0.005), and no prior hea rt failure hospitalizations within the past year (p=0.001) were found to be inde pendent predictors of low ACE inhibitor dosing. Conclusions: In this heart failu re benchmarking project, elderly patients received guideline-based ACEinhibitor therapy at similar rates, but at lower doses, compared to their younger counter parts. Copyright. Purpose: this purpose was this study was to determine the age dependence, the prior studies suggest that eld erly cohorts are less likely to receive such therapy. of adherence to guideline-based medical car e in hospitalized heart failure patients. Methods: We performed a multicenter ob servational cohort study including 613 patients admitted to consulting hospit als with a primary diagnosis of heart failure with ejection fraction ≤ 40%. Thi s cohort was divided into four age groups (group 1: <60, group 2: 60-69, group 3: 70-79, and group 4:80 years) and adherence to guideline-based medical care was measured. Results: ACE inhibitors were administered to 83% of ideal heart failu re patients, and this rate was similar for all age groups. Elderly patients receved significantly lower ACE inhibitor dosages compared to their younger counter parts (168, 148, 125 and 117 mg captopri (p <0.001), prior residence in a long-term care facility (p = 0.037), intolerance to ACE inhibitors (p = 0.006), lower blood pr essure (p = 0.005), absence of a history of hypertension (p = 0.005), and no prior hea rt failure hospitalizations within the past year (p = 0.001) were found to be inde pendent predictors of low ACE inhibitor dosing. Conclusions: In this heart failu re benchmarking project, elderly patients received guideline-based ACE inhibitor therapy at similar rates, but at lower doses, compared to their younger counter parts. Copyright.