Community-acquired pneumonia (CAP) is one of the leading causes of morbidity and mortality worldwide, often leading to hospital admissions. In Portugal, the factors associated with in-hospital mortality due to CAP are not fully documented. The aim of this study was to characterize the trends of CAP hospitalization in all age groups and the factors associated with their mortality between 2000 and 2014.
We conducted a cross-sectional study using CAP hospitalization data in all age groups, in Portugal Mainland. Logistic regression was used to identify the factors associated with in-hospital mortality.
Between 2001 and 2011, CAP hospitalization rate increased from 2.8 to 4.3 per 1000 population. Hospitalization rates were higher in the extreme ages ( ≤ 4 and  ≥ 75 years). However, a decrease in the hospitalization rate and its mortality was observed, in the younger ages. A total of 548,699 hospitalization CAP episodes, between 2000 and 2014, were analyzed, with male (56.2%) and elderly ≥65 years (91.7%) predominance, resulting in 101,740 deaths (18.5%). Men had a significantly lower mean age (64.3 ± 26.4 years versus 67.9 ± 27.5 years; p < 0.001). During the studied 15 years, there was an increase of 45.2% in the number of annual hospitalizations, concomitant with the admission increase of individuals aged over 75 years. Since 2012 a decrease in hospitalizations and associated deaths were detected. The increase in age represented a progressive and significant rise in the probability of death, except for the age group 1-4 years. The age group ≥85 years old (Adjusted OR = 124.256; 95%CI: 97.838-157.807) and males (Adjusted OR = 1.261; 95%CI: 1.243-1.280) were significantly associated with death risk for CAP hospitalization. After 2010, this risk decreased (Adjusted OR = 0.961; 95%CI: 0.940-0.982). The main factors affecting mortality were age, sex, unemployment rate, number of performed procedures and admission quinquennia.
Despite a trend of decrease in CAP hospitalizations and associated death since 2012, the numbers of in-hospital mortality showed, in the 15 years under analysis, an overall increase over time, mainly associated with age, in particular very old people ( ≥ 75 years), males and a higher parish unemployment rate. Therefore, the implementation of CAP preventive measures should be reinforced in these vulnerable groups.