Predictors of mortality and length of stay in hospitalized cases of 2009 influenza A (H1N1): Experiences of a tertiary care center

摘要

Aim: To study the clinical characteristics and outcome of admitted patients of H1N1 (hemagglutinin -H neuraminidase -N) influenza in a tertiary level hospital, from Oct 2009 to Dec 2010. Materials and Methods: A retrospective analysis of 77 confirmed patients admitted in this unit with H1N1 infection. Results: Of the 77 patients studied, 33 (42.8%) were female. Mean age was 40.88 ± 13.45 years, majority (70.13%) being less than 50 years. Thirty eight (49.3%) patients had at least one co-morbidity, diabetes mellitus being the most common (n = 15, 19.5%). The most common presenting symptom was fever in 75 (97.4%) patients, cough in 67 (87%) and dyspnoea in 59 (76.6%) patients. At admission, mean PaO2/FiO2 ratio was 213.16 ± 132.75 mmHg (n = 60) while mean PaCO ₂ was 40.14 ± 14.86 mmHg. One or more organ failure was present in 45 (58.4%) patients. Nineteen (24.60%) patients required invasive mechanical ventilation. Circulatory failure was observed in 10 (13%) patients while 2 patients required hemodialysis. Overall, 13% mortality (n = 10) was observed. PaCO ₂ level at admission (OR 1.093; 95% confidence interval: 1.002-1.193; P = 0.044) and number of organ failure (OR 8.089; 95% confidence interval: 1.133-57.778; P = 0.037) were identified as independent risk- factors for mortality. Conclusion: Increased duration of dyspnoea prior to admission, pneumonia, low PaO ₂ /FiO ₂ ratio at admission and 24 hours later, higher PaCO ₂ values on admission, higher O ₂ requirement, number of organ failures and use of corticosteroids and delay in specialized treatment were associated with a poorer outcome.