Characteristics and trends in the incidence of adults hospitalised with community-acquired pneumonia (CAP) in Portugal, 2010-18

Community-acquired pneumonia (CAP) is a major cause of hospitalization, resulting in substantial morbidity, mortality and costs. Evaluating CAP trends over time is important to understand changing patterns or the impact of public health interventions. This study aims to describe the characteristics and trends in the incidence of adults hospitalised with CAP in Portugal. In this retrospective cohort study, we included hospitalization data, prevalence of comorbidities, and population data. CAP hospitalisations (CAP-H) of adults (≥18y) living in mainland Portugal discharged from a public hospital in 2010-18 were identified using ICD-9-CM or ICD-10-CM codes. Based on previous CAP studies, we selected nine relevant comorbidities. We described the frequency and incidence of CAP-H per gender, age group, comorbidity and year of discharge. Trends were explored using Joinpoint regression. We observed 469,944 CAP-H during 2010-18. The majority were ≥75 years (66%) and 55% were male. Most frequent recorded comorbidities were congestive heart failure (27%), diabetes (26%), and chronic pulmonary disease (19%). The frequency of CAP-H ranged between 57,721 in 2012 and 45,910 in 2018. The Joinpoint regression identified a gradual decline in the incidence rates of CAP-H for both genders and all age groups. CAP-H decreased over time among patients with diabetes or AIDS/HIV while increased for CRD patients. For the remaining 6 comorbidities, an upward trend was followed by a decreasing trend (Table 1). The findings of our study offer valuable insights for selecting priority groups for public health interventions and design strategies to mitigate the burden of CAP.