[Epidemiology of pneumococcal pneumonia among middle-aged and older adults in Catalonia, 2017-2018]. / Epidemiología de la neumonía neumocócica en adultos mayores de 50 años: estudio de cohortes en Cataluña, 2017-2018.

ABSTRACT

OBJECTIVE: To analyse population-based incidence and lethality of pneumococcal pneumonia (PP) requiring hospitalisation among Catalonian adults after universal vaccination implementation in infants. DESIGN: Population-based cohort study. SETTING: Primary care/hospital, Catalonia. PARTICIPANTS: 2,059,645 individuals ≥50 years old affiliated to the Institut Catala de la Salut retrospectively followed between 01/01/2017 and 31/12/2018. MAIN OUTCOME MEASURES: The Catalonian information system for the development of research in primary care (SIDIAP, Sistema de Información para el Desarrollo de la Investigación en Atención Primaria) was used to establish baseline characteristics and risk-strata of cohort members at study start low-risk (immunocompetent persons without risk conditions), intermediate-risk (immunocompetent persons with at-risk condition) and high-risk (immunocompromising conditions). PP requiring hospitalisation among cohort members across study period were collected from CMBD (Conjunto Mínimo Básico de Datos) discharge data of 64 reference Catalonian hospitals. RESULTS: An amount of 3592 episodes of HPP were observed, with an incidence density of 90.7 cases per 100,000 person-years (95% CI 85.2-96.5), being 11.9 bacteremic (95% CI 10.8-13.1) and 78.8 non-bacteremic (95% CI 74.0-83.8). Incidence rates substantially increased by age (37.3 in 50-64 years vs. 98.3 in 65-79 years vs. 259.8 in ≥80 years) and baseline-risk stratum (42.1, 120.7 and 238.6 in low-, intermediate- and high-risk stratum, respectively). Overall case-fatality rate was 7.6% (10.8% in invasive cases vs. 7.1% in non-invasive cases; pP=.004). In multivariable analyses, high-risk stratum and oldest age were the strongest predictors for invasive and non-invasive cases, respectively. CONCLUSION: Incidence and lethality of PP remained moderate among adults >50 years in Catalonia during 2017-2018 (earlier period after universal vaccination introduction for infants).