Host characteristics predict outcome among adult patients admitted by severe acute respiratory infection

Background: Except for influenza pandemics, different observational studies have failed to demonstrate differences in mortality between various etiologies in adult patients hospitalized for respiratory infections. Aim: To compare clinical and mortality differences between different viral pathogens associated with severe acute respiratory infections (SARI) in hospitalized adults. Material and Methods: One-year prospective study in a sentinel center. We included 132 patients with SARI hospitalized for any of the nine viruses under study by PCR. Clinical variables were compared, excluding cases of coinfection. Results: A viral coinfection was identified in 12% and influenza infection in 56% of cases. Eighty percent of patients were aged >= 65 years, with a high frequency of comorbidities, 27% were bedridden. Twenty four percent were admitted to critical care units, 20% required ventilatory assistance and 16% died. Cases occurred throughout the year, with an expected seasonal peak between autumn and spring and a predominance of infections not associated with influenza during summer months. In the multivariate analysis, only being bedridden was significantly associated with mortality at discharge (Odds ratio 23.46; 95% confidence intervals 3.33-165.12, p < 0.01), without association with age, comorbidity, viral pathogen involved, laboratory parameters, clinical presentation or CURB65 score. No major clinical dissimilarities were found between different viral pathogens. Conclusions: In our series of patients, mostly elderly, only bedridden status was significantly associated with mortality at discharge in patients hospitalized for SARI. Viral pathogens were not relevant.