Trends in Hospitalization, Case Fatality, and Mortality for Community-Acquired Pneumonia in Portugal over 20 Years

Community-acquired pneumonia (CAP) remains a leading cause of morbidity and mortality worldwide and a major driver of hospital admissions. Older adults are disproportionately affected, owing to immune senescence and a higher prevalence of chronic comorbidities. This study examined two decades (2000-2019) of adult hospital admissions for CAP in mainland Portugal.

We analyzed adult CAP hospitalizations between 2000 and 2019 from the Portuguese Mainland Hospital Diagnosis National Database. We assessed all hospitalizations attributable to CAP over the 20 years, stratified by age group, and examined seasonal variation. Trends in hospital length of stay and in-hospital case fatality were evaluated.

Between 2000 and 2019, the adult CAP hospitalization rate in Portugal rose from 3.61 to 5.28 per 1000 persons-year. This was fostered by patients older than 80 years, who grew from 30.4% to 53.1% of CAP admissions. The mean age increased over time, from 70.1 ± 17.0 years to 77.7 ± 14.1 years. Hospitalization episodes of patients older than 85 years admitted for CAP increased fourfold. CAP-associated case fatality increased slightly, driven by patients older than 80 years. A modest decline was noted from 2016 to 2019 (from 23.1% to 21.8%). This was strongly correlated with mean age. Invasive mechanical ventilation was offered in a growing number of hospitalization episodes of CAP (from 3.1% in 2000 to 7.5% in 2019) but with significant age imbalance. Admissions peaked in January, whereas case fatality was highest during the summer months.

These findings underscore the growing burden of CAP on healthcare systems, driven by an aging population and rising life expectancy. This has implications for both resource allocation and preventive strategies.