Community-acquired pneumonia mortality trends according to age and gender: 2009 to 2019

Community-acquired pneumonia (CAP) is one of the leading causes of morbidity and mortality worldwide. It remains unknown whether recently introduced prevention strategies, such as vaccination, may have impacted its mortality. Moreover, it is important to understand whether these trends are similar for all patients or if some groups may have different outcomes.

We evaluated the CAP hospitalization data for adult patients, from the Portuguese mainland Hospital diagnosis database. We included all patients discharged with CAP between 2010 and 2019. We assessed Hospital mortality for the whole population and according to age and gender. We also examined the monthly number of admissions and mortality.  RESULTS: We identified 462,910 CAP admissions, of which 54% were male (mean age 76.8 ± 14.5years). We divided our population into 4 age groups: 18-40years (3.2% of episodes); 41-65years (14.9%); 66-80years (31.6%); >80 years (50.2%). Mortality increased sharply with age, to more than 40% in older patients, highlighting the disproportionate burden of respiratory diseases in this age group. Although CAP mortality remained stable until 2016 (roughly 23%), a slight decreasing trend was noted afterwards (from 23.1 to 21.8%). In hospitalized patients, the relative risk of dying with CAP, consistently decreased during this period, from odds ratio 5.5, 95% CI 5.4-5.7 to odds ratio 4.3, 95% CI 4.2-4.4. As much as 25% of deaths related to CAP occurred during the first 48 h after hospital admission. While CAP admissions peaked in January, mortality was higher during the summertime.

Community-acquired pneumonia remains associated with a high risk of death. Mortality increased with age from 40 years onwards. However, the relative risk of dying with CAP in the Hospital decreased during this decade.