Incidence, Etiology, and Outcomes of Community-Acquired Pneumonia: A Population-Based Study

Bjarnason, Agnar; Westin, Johan; Lindh, Magnus; Andersson, Lars-Magnus; Kristinsson, Karl G; Löve, Arthur; Baldursson, Olafur; Gottfredsson, Magnus

This population-based study with a 95% inclusion rate demonstrates an incidence of CAP requiring hospitalization of 20.6 cases per 10 000 adults/year. S pneumoniae was the most frequently identified pathogen. The incidence of M pneumoniae was highest amongst the oldest patients, similar to the other pathogens examined. Study designs that exclude participants with prior antibiotic use or unable to produce sputum to increase diagnostic yield may lead to biased results and miss certain pathogens. Clinical signs and symptoms were of limited use for identifying patients with a respiratory virus or atypical bacterial infection, and, despite lower severity scores among these patients, LOS and rates of ICU admission and need for assisted ventilation were similar regardless of microbial etiology.