RT Journal Article T1 Influenza A H1N1 Community-Acquired Pneumonia: Characteristics and Risk Factors—A Case-Control Study A1 Abelleira París, Romina A1 Ruano Raviña, Alberto A1 Lama López, Adriana A1 Barbeito Castiñeiras, Gema A1 Toubes Navarro, María Elena A1 Domínguez Antelo, Elena A1 González Barcala, Francisco Javier A1 Rodríguez Núñez, Nuria A1 Marcos Rodríguez, Pedro Jorge A1 Pérez del Molino Bernal, María Luisa A1 Valdés Cuadrado, Luis AB Introduction. Influenza A H1N1 community-acquired pneumonia (CAP) is a quite frequent respiratory disease. Despite being considered more serious than other CAPs, there are very few studies comparing its characteristics with noninfluenza CAP. We aim to establish the differences between pneumonia due to H1N1 virus and pneumonia not caused by H1N1 influenza virus and to determine the probability that a pneumonia is due to an H1N1 virus infection based on the most relevant variables. Methods. We used a case-control study where cases were H1N1 CAP patients with confirmed microbiological diagnosis and controls were patients with CAP admitted to hospital. H1N1 and other influenza types were discarded among controls. We calculated the probability of being a case or control using multivariate logistic regression. Results. We included 99 cases and 270 controls. Cases were younger than controls (53 vs 71 years, respectively). Mortality was much higher for H1N1 patients (13% vs 0.3%), and admission to intensive care unit was more frequent for H1N1 cases. The variables most associated with presenting H1N1 CAP were bilateral affectation on chest X-rays (OR: 5.70; 95% CI 2.69–10.40), followed by presence of arthromyalgias, with cases presenting close to three times more arthromyalgias compared to controls. Low leukocytes count and high AST values were also significantly associated with H1N1 CAP. H1N1 CAPs are characterized by bilateral affectation, low leukocyte count, presence of arthromyalgias, and high AST. Conclusions. A few and easy to obtain clinical parameters might be extremely useful to distinguish H1N1 CAP from CAPs of other origin. PB Hindawi SN 1198-2241 YR 2019 FD 2019 LK http://hdl.handle.net/10347/21385 UL http://hdl.handle.net/10347/21385 LA eng NO Abelleira, R., Ruano-Ravina, A., Lama, A., Barbeito, G., Toubes, M., & Domínguez-Antelo, C. et al. (2019). Influenza A H1N1 Community-Acquired Pneumonia: Characteristics and Risk Factors—A Case-Control Study. Canadian Respiratory Journal, 2019, 1-8. doi: 10.1155/2019/4301039 DS Minerva RD 9 jun 2026