Incidence rate of community-acquired pneumonia in adults: a population-based prospective active surveillance study in three cities in South America

OBJECTIVE: To determine the incidence rate and mortality of community-acquired pneumonia (CAP) in adults in three cities in Latin America during a 3-year period. DESIGN: Prospective population-based surveillance study. SETTING: Healthcare facilities (outpatient centres and hospitals) in the cities of General Roca (Argentina), Rivera (Uruguay) and Concepción (Paraguay). PARTICIPANTS: 2302 adults aged 18 years and older with CAP were prospectively enrolled between January 2012 and March 2015. MAIN OUTCOME MEASURES: Incidence rates of CAP in adults, predisposing conditions for disease, mortality at 14 days and at 1 year were estimated. Incidence rate of CAP, within each age group, was calculated by dividing the number of cases by the person-years of disease-free exposure time based on the last census; incidence rates were expressed per 1000 person-years. RESULTS: Median age of participants was 66 years, 46.44% were men, 68% were hospitalised. Annual incidence rate was 7.03 (95% CI 6.64 to 7.44) per 1000 person-years in General Roca, 6.33 (95% CI 5.92 to 6.78) per 1000 person-years in Rivera and 1.76 (95% CI 1.55 to 2.00) per 1000 person-years in Concepción. Incidence rates were highest in participants aged over 65 years. 82.4% had at least one predisposing condition and 48% had two or more (multimorbidity). Chronic heart disease (43.6%) and smoking (37.3%) were the most common risk factors. 14-day mortality rate was 12.1% and 1-year mortality was 24.9%. Multimorbidity was associated with an increased risk of death at 14 days (OR 2.91; 95% CI 2.23 to 3.80) and at 1 year (OR 3.00; 95% CI 2.44 to 3.70). CONCLUSIONS: We found a high incidence rate of CAP in adults, ranging from 1.76 to 7.03 per 1000 person-years, in three cities in South America, disclosing the high burden of disease in the region. Efforts to improve prevention strategies are needed.