Risk factors associated with mortality in patients infected with influenza A/H1N1 in Mexico.

ABSTRACT

BACKGROUND: Influenza virus pandemics vary dramatically in their severity and mortality. Thus, it is very important to identify populations with high risks of developing severe illness to reduce mortality in future pandemics. The purpose was to determine the mortality-associated risk factors in hospitalized Mexican patients infected with influenza A/H1N1. RESULTS: The risk factors associated with mortality were male sex [odds ratio (OR) = 5.25, confidence interval (CI) = 1.22-28.95], medical attention delayed >3 days (OR = 9.9, CI = 1.51-64.52), anti-flu therapy delayed >3 days (OR = 10.0, CI = 1.07-93.43), admission to intensive care unit (ICU) (OR = 9.9, CI = 1.51-64.52) and creatinine levels >1.0 mg/dL when admitted to hospital (OR = 11.2, CI = 1.05-120.32). After adjusting for the effects of potentially confounding variables in a logistic regression model, delayed medical attention (OR = 13.91, CI = 1.09-41.42, p = 0.044) and ICU hospitalization (OR = 11.02, CI = 1.59-76.25, p = 0.015) were the only predictors of mortality. CONCLUSION: Early medical attention is essential for reducing the mortality risk in patients with influenza A/H1N1, while a requirement for ICU management increases the risk.