Influenza A H1N1 infections carry a significant mortality risk. This study describes inpatients with suspected and confirmed Influenza A H1N1 infection who were prescribed oseltamivir, the risk factors associated with infection, the association between infection and mortality, and the factors associated with in-hospital mortality in infected patients.


This study was a matched case-control study of hospitalized patients who underwent real-time polymerase chain reaction testing for Influenza A H1N1 and were treated with oseltamivir from 2009 to 2015 in a tertiary care hospital. Cases (patients with positive Influenza A H1N1 testing) were matched 1:1 to controls (patients with negative test results).


A total of 1405 inpatients who underwent PCR testing and received treatment with oseltamivir were identified in our study and 157 patients confirmed Influenza A H1N1. Almost one third of patients with Influenza A H1N1 were diagnosed in the pandemic period. There was no difference in mortality between cases and controls. Immunocompromised status, requirement of vasoactive drugs, mechanical ventilation, acute hemodialysis, albumin administration, surgical procedures and thoracic procedures and length of stay were associated with increased risk of death in Influenza A H1N1 infected patients.


We found no increased risk of mortality for patients with proven Influenza A H1N1 when compared to similar patients without confirmed Influenza.

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