Community-acquired pneumonia in hospitalised patients: changes in aetiology, clinical presentation, and severity outcomes in a 10-year period

Abstract Background and objective Community-acquired pneumonia (CAP) is a frequent cause of hospitalisation. Several factors, such as pandemics, vaccines and globalisation may lead to changes in epidemiology, clinical presentation, and outcomes of CAP, which oblige to a constant actualisation. We performed this study to analyse how these factors have evolved over a 10-year period. Materials and methods Patients diagnosed with CAP for two 1-year periods that were 10 years apart (2007–2008 and 2017–2018) were included. We compared microbiological information, clinical data and evolutive outcomes in the two periods. A mortality analysis was performed. Results 1043 patients were included: 452 during the first period (2007- 2008), and 591 during the second period (2017–2018). Bacterial aetiology did not change during the 10-year period, besides a slight increase in Staphylococcus aureus (0.9% vs 2.9%, p = 0.026). There was a decline in the proportion of bacteraemia in the second period (14.8% vs 9.6%, p = 0.012). The incidence of complicated pleural effusion and septic shock declined too (6.4% vs 3.6%, p = 0.04 and 15.5% vs 6.3%, p < 0.001). Respiratory failure and Intensive care unit (ICU) admission were similar in both periods. Variables independently associated with mortality were age and septic shock. Influenza vaccine was a protective factor against mortality in the second period. Conclusions We have not found relevant differences in the bacterial aetiology of CAP over this 10-year period. There has been a decline in septic complications of CAP such as septic shock, bacteraemia, and complicated pleural effusion. Influenza vaccination is an important tool to reduce mortality. KEY MESSAGES There were no differences in the bacterial pathogens causing CAP among the 10-year study period. There has been a decline in septic complications of CAP such as septic shock, bacteraemia, and complicated pleural effusion.