Clinical profile and predictors of mortality of severe pandemic (H1N1) 2009 virus infection needing intensive care: A multi-centre prospective study from South India

Background: This multi-center study from India details the profile and outcomes of patients admitted to the intensive care unit (ICU) with pandemic Influenza A (H1N1) 2009 virus [P(H1N1)2009v] infection. Materials and Methods: Over 4 months, adult patients diagnosed to have P(H1N1)2009v infection by real-time RT-PCR of respiratory specimens and requiring ICU admission were followed up until death or hospital discharge. Sequential organ failure assessment (SOFA) scores were calculated daily. Results: Of the 1902 patients screened, 464 (24.4%) tested positive for P(H1N1)2009v; 106 (22.8%) patients aged 35±11.9 (mean±SD) years required ICU admission 5.8±2.7 days after onset of illness. Common symptoms were fever (96.2%), cough (88.7%), and breathlessness (85.9%). The admission APACHE-II and SOFA scores were 14.4±6.5 and 5.5±3.1, respectively. Ninety-six (90.6%) patients required ventilation for 10.1±7.5 days. Of these, 34/96 (35.4%) were non-invasively ventilated; 16/34 were weaned successfully whilst 18/34 required intubation. Sixteen patients (15.1%) needed dialysis. The duration of hospitalization was 14.0±8.0 days. Hospital mortality was 49%. Mortality in pregnant/puerperal women was 52.6% (10/19). Patients requiring invasive ventilation at admission had a higher mortality than those managed with non-invasive ventilation and those not requiring ventilation (44/62 vs. 8/44, P<0.001). Need for dialysis was independently associated with mortality (P=0.019). Although admission APACHE-II and SOFA scores were significantly (P<0.02) higher in non-survivors compared with survivors on univariate analysis, individually, neither were predictive on multivariate analysis. Conclusions: In our setting, a high mortality was observed in patients admitted to ICU with severe P(H1N1)2009v infection. The need for invasive ventilation and dialysis were associated with a poor outcome