Aims: Previous heart failure (HF) trials suggested that age influences patient characteristics and outcome; however, under-representation of elderly patients has limited characterization of this cohort. Whether standard prognostic variables have differential utility in various age groups is unclear. Methods and results: The PROTECT trial investigated 2033 patients (median age 72 years) with acute HF randomized to rolofylline or placebo. Patients were divided into five groups based on the quintiles of age: ≤59, 60–68, 69–74, 75–79, and ≥80 years. Baseline characteristics, medications, and outcomes (30-day death or cardiovascular/renal hospitalization, and death at 30 and 180 days) were explored. The prognostic utility of baseline characteristics for outcomes was investigated in the different groups and in those aged