Abstract
Background: Acute heart failure (AHF) is a common reason for emergency care, yet data on its epidemiology and prognosis in the prehospital setting remain limited. This study aims to analyze the characteristics and long-term survival outcomes of patients with AHF managed by emergency medical services (EMSs). Methods: A multicenter, prospective, observational study was conducted in adult patients attended by EMSs and transferred to emergency departments (EDs). Collected data included demographics, vital signs, laboratory parameters, chronic obstructive pulmonary disease (COPD) history, comorbidity burden assessed using the Age-adjusted Charlson Comorbidity Index (aCCI), and clinical outcomes. The primary endpoint was 2-year mortality (M2Y). Survival analysis was performed using Cox regression and Kaplan-Meier analysis. Results: A total of 417 patients were included. Their median age was 84 years, and 48.2% were women. A total of 92.3% of the patients had an elevated aCCI. Overall, M2Y was 57.6%, rising to 74.4% among COPD patients. aCCI range and elevated plasma potassium and lactate levels were independently associated with reduced survival (HR 2.86, 1.45 and 1.15, respectively). Overall, 50% of all deaths occurred within the first 49 days. Conclusions: AHF patients attended by EMSs exhibited high 2-year mortality, likely due to advanced age and comorbidities. High comorbidity burden and abnormal potassium and lactate levels were linked to worse outcomes.