Characteristics of Hospitalized Patients with Severe and Non-Severe Pandemic Influenza A (H1N1) in Saurashtra Region, India (Two Waves Analysis)

BACKGROUND: In India, the first case of 2009 pandemic influenza A (H1N1) virus infection was reported in May 2009 and the same in Saurashtra region in August 2009. We describe the epidemiology and factors associated with severe and non-severe cases of 2009 influenza A (H1N1) infection reported in the Saurashtra region. MATERIALS AND METHODS: From September 2009 to January 2011, we reported 511 patients who were infected with 2009 influenza A (H1N1) virus and admitted in different hospitals of Rajkot city. Real-time reverse transcriptase polymerase chain reaction (RT-PCR) testing was used to confirm infection. Factors associated with severe cases were determined by comparing with non-severe cases. RESULTS: Out of 511 patients, 140 had severe disease (requiring intensive care or died) and 371 non-severe diseases (admitted in wards and survived). Median age of 30 years; median time of 5 days from onset of illness to diagnosis, and 4 days median time was reported for hospital stay among severe disease patients. More than half (60.7%) were females. Out of the patients with severe disease, 52.1% patients residing in urban area (OR = 1.68, CI = 1.13-2.49). Significant association was reported among severe disease patients for delayed referral from general practitioner/physician after initial treatment. All patients received antiviral drug, however, only 27.1% received within 2 days of illness. Presence of coexisting condition (pregnancy (OR = 0.19, CI = 0.08-0.48) was strongly associated with severe disease. CONCLUSION: Delayed referral from general practitioner/physician, duration of antiviral treatment, presence of coexisting condition (i.e., pregnancy) were responsible for intensive care or mortality among severe influenza A (H1N1) illness.