Háskóli ÍslandsUniversity of IcelandBjarnason, AgnarWestin, JohanLindh, MagnusAndersson, Lars-MagnusKristinsson, Karl G.Löve, ArthurBaldursson, ÓlafurGottfredsson, Magnus2018-07-312018-07-312018-02-01Agnar Bjarnason, Johan Westin, Magnus Lindh, Lars-Magnus Andersson, Karl G Kristinsson, Arthur Löve, Olafur Baldursson, Magnus Gottfredsson; Incidence, Etiology, and Outcomes of Community-Acquired Pneumonia: A Population-Based Study, Open Forum Infectious Diseases, Volume 5, Issue 2, 1 February 2018, ofy010, https://doi.org/10.1093/ofid/ofy0102328-8957https://hdl.handle.net/20.500.11815/750Background The microbial etiology of community-acquired pneumonia (CAP) is often unclear in clinical practice, and previous studies have produced variable results. Population-based studies examining etiology and incidence are lacking. This study examined the incidence and etiology of CAP requiring hospitalization in a population-based cohort as well as risk factors and outcomes for specific etiologies. Methods Consecutive admissions due to CAP in Reykjavik, Iceland were studied. Etiologic testing was performed with cultures, urine-antigen detection, and polymerase chain reaction analysis of airway samples. Outcomes were length of stay, intensive care unit admission, assisted ventilation, and mortality. Results The inclusion rate was 95%. The incidence of CAP requiring hospitalization was 20.6 cases per 10000 adults/year. A potential pathogen was detected in 52% (164 of 310) of admissions and in 74% (43 of 58) with complete sample sets. Streptococcuspneumoniae was the most common pathogen (61 of 310, 20%; incidence: 4.1/10000). Viruses were identified in 15% (47 of 310; incidence: 3.1/10000), Mycoplasmapneumoniae were identified in 12% (36 of 310; incidence: 2.4/10000), and multiple pathogens were identified in 10% (30 of 310; incidence: 2.0/10000). Recent antimicrobial therapy was associated with increased detection of M pneumoniae (P < .001), whereas a lack of recent antimicrobial therapy was associated with increased detection of S pneumoniae (P = .02). Symptoms and outcomes were similar irrespective of microbial etiology. Conclusions Pneumococci, M pneumoniae, and viruses are the most common pathogens associated with CAP requiring hospital admission, and they all have a similar incidence that increases with age. Symptoms do not correlate with specific agents, and outcomes are similar irrespective of pathogens identified.UNSP ofy010eninfo:eu-repo/semantics/openAccessCommunity acquired pneumoniaEtiologyIncidenceMycoplasma pneumoniaeStreptococcus pneumoniaeLungnabólgaAlgengi sjúkdómainfo:eu-repo/semantics/articleOpen Forum Infectious Diseases10.1093/ofid/ofy010