Clinical characteristics, evolution, and treatment-related risk factors for mortality among immunosuppressed patients with influenza A (H1N1) virus admitted to the intensive care unit.

PURPOSE: Information about immunocompromised patients infected with influenza A (H1N1) virus and requiring admission to the ICU is lacking. Our objective was to know the clinical characteristics of these patients and to identify treatment-related variables associated with mortality. MATERIAL AND METHODS: A prospective multicenter observational cohort study was based on data from a Spanish registry (2009-2015) collected by 148 Spanish ICUs. All patients admitted to the ICU with the diagnosis of influenza A (H1N1) virus infection were included. Immunosuppression was clearly defined. Factors associated with mortality in immunocompromised patients were assessed by conventional logistic regression analysis and by a propensity score (PS) adjusted-multivariable analysis. RESULTS: Of 1899 patients with influenza A (H1N1) infection, 238 (12.5%) were classified as immunocompromised. Mortality was significantly higher in immunosuppressed patients. Four variables independently associated with mortality were identified: SOFA score, need of vasopressor, use of corticosteroids, and acute renal failure, AKIN 3 stage. In the PS-adjusted model, corticosteroid therapy remained as an independent factor associated with increased mortality (OR 2.25;95%CI, 1.15-4.38;p = 0.017). In the subgroup of hematological patients (n = 141), corticosteroid therapy was also associated with increased mortality (OR 3.12; 95%CI, 1.32-7.41; p = 0.010). CONCLUSION: Immunocompromised individuals with influenza A (H1N1) admitted to the ICU have a poor outcome. In this population, the use of corticosteroids is strongly discouraged.