Indian Journal of Critical Care Medicine

Register      Login



Volume / Issue

Online First

Related articles

VOLUME 17 , ISSUE 5 ( October, 2013 ) > List of Articles


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

Bipin Narayanrao Jibhkate

Keywords : 2009 influenza A, H1N1, hospitalized, length of stay, mortality, predictors

Citation Information : Jibhkate BN. Predictors of mortality and length of stay in hospitalized cases of 2009 influenza A (H1N1): Experiences of a tertiary care center. Indian J Crit Care Med 2013; 17 (5):275-282.

DOI: 10.4103/0972-5229.120318

License: CC BY-ND 3.0

Published Online: 01-08-2014

Copyright Statement:  Copyright © 2013; The Author(s).


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.

PDF Share
  1. Centers for Disease Control and Prevention (CDC). Outbreak of swine-origin influenza A (H1N1) virus infection-Mexico, March-April 2009. MMWR Morb Mortal Wkly Rep 2009;58:467-70.
  2. Centers for Disease Control and Prevention (CDC). Swine-origin influenza A (H1N1) virus infections in a school-New York City, April 2009. MMWR Morb Mortal Wkly Rep 2009;58:470-2.
  3. Centers for Disease Control and Prevention (CDC). Swine influenza A (H1N1) infection in two children - Southern California, March-April 2009. MMWR Morb Mortal Wkly Rep 2009;58:400-2.
  4. Influenza A (H1N1)-update 14. Geneva: World Health Organization; 2009. Available from: [Last accessed on 2009 May 04].
  5. Weekly Data of Influenza A H1N1 (For the week ending 2 nd January 2011) and cumulative no. of Lab confirmed cases and deaths-State wise. New Delhi: Office of the Director, Emergency Medical Relief, Directorate General of Health Services, India; 2011. Available from: [Last accessed on 2011 Jan 02].
  6. Louie JK, Acosta M, Winter K, Jean C, Gavali S, Schechter R, et al. Factors associated with death or hospitalization due to pandemic 2009 influenza A (H1N1) infection in California. JAMA 2009;302:1896-902.
  7. Domínguez-Cherit G, Lapinsky SE, Macias AE, Pinto R, Espinosa-Perez L, de la Torre A, et al. Critically Ill patients with 2009 influenza A (H1N1) in Mexico. JAMA 2009;302:1880-7.
  8. Perez-Padilla R, de la Rosa-Zamboni D, Ponce de Leon S, Hernandez M, Quiñones-Falconi F, Bautista E, et al. Pneumonia and respiratory failure from swine-origin influenza A (H1N1) in Mexico. N Engl J Med 2009;361:680-9.
  9. Gómez-Gómez A, Magaña-Aquino M, Garcia-Sepúlveda C, Ochoa-Pérez UR, Falcón-Escobedo R, Comas-García A, et al. Severe pneumonia associated with pandemic (H1N1) 2009 outbreak, San Luis Potosí, Mexico. Emerg Infect Dis 2010;16:27-34.
  10. Jain S, Kamimoto L, Bramley AM, Schmitz AM, Benoit SR, Louie J, et al. Hospitalized patients with 2009 H1N1 influenza in the United States, April-June 2009. N Engl J Med 2009;361:1935-44.
  11. Novel Swine-Origin Influenza A (H1N1) Virus Investigation Team, Dawood FS, Jain S, Finelli L, Shaw MW, Lindstrom S, Garten RJ, et al. Emergence of a novel swine-origin influenza A (H1N1) virus in humans. N Engl J Med 2009;360:2605-15.
  12. Thompson WW, Shay DK, Weintraub E, Brammer L, Bridges CB, Cox NJ, et al. Influenza-associated hospitalizations in the United States. JAMA 2004;292:1333-40.
  13. Kumar A, Zarychanski R, Pinto R, Cook DJ, Marshall J, Lacroix J, et al. Critically ill patients with 2009 influenza A (H1N1) infection in Canada. JAMA 2009;302:1872-9.
  14. van ′t Klooster TM, Wielders CC, Donker T, Isken L, Meijer A, van den Wijngaard CC, et al. Surveillance of hospitalisations for 2009 pandemic influenza A (H1N1) in the Netherlands, 5 June-31 December 2009. Euro Surveill 2010;15:pii=19461.
  15. Chen KF, Gaydos C, Rothman RE. Update on emerging infections: News from the Centers for Disease Control and Prevention. Hospitalized patients with novel influenza A (H1N1) virus infection - California, April-May, 2009. Ann Emerg Med 2009;54:732-6.
  16. Xi X, Xu Y, Jiang L, Li A, Duan J, Du B, et al. Hospitalized adult patients with 2009 influenza A (H1N1) in Beijing, China: Risk factors for hospital mortality. BMC Infect Dis 2010;10:256.
  17. Hanslik T, Boelle PY, Flahault A. Preliminary estimation of risk factors for admission to intensive care units and for death in patients infected with A (H1N1) 2009 influenza virus, France, 2009-2010. PLoS Curr 2010;2:RRN1150.
  18. Abramowitz LJ. The effect of Asian influenza on pregnancy. S Afr Med J 1958;32:1155-6.
  19. Beigi RH. Pandemic influenza and pregnancy: A call for preparedness planning. Obstet Gynecol 2007;109:1193-6.
  20. Dodds L, McNeil SA, Fell DB, Allen VM, Coombs A, Scott J, et al. Impact of influenza exposure on rates of hospital admissions and physician visits because of respiratory illness among pregnant women. CMAJ 2007;176:463-8.
  21. Lapinsky SE. H1N1 novel influenza A in pregnant and immunocompromised patients. Crit Care Med 2010;38:e52-e57.
  22. Jamieson DJ, Honein MA, Rasmussen SA, Williams JL, Swerdlow DL, Biggerstaff MS, et al. H1N1 2009 influenza virus infection during pregnancy in the USA. Lancet 2009;374:451-8.
  23. Pandemic (H1N1) 2009-Brief note 8. Geneva: World Health Organization; 2009. Available from: 20090820/en/index.html.
  24. Cui W, Zhao H, Lu X, Wen Y, Zhou Y, Deng B, et al. Factors associated with death in hospitalized pneumonia patients with 2009 H1N1 influenza in Shenyang, China. BMC Infect Dis 2010;10:145.
  25. ANZIC Influenza Investigators, Webb SA, Pettilä V, Seppelt I, Bellomo R, Bailey M, et al. Critical care services and 2009 H1N1 influenza in Australia and New Zealand. N Engl J Med 2009;361:1925-34.
  26. Rothberg MB, Haessler SD, Brown RB. Complications of viral influenza. Am J Med 2008;121:258-64.
  27. Treanor J. Influenza virus. In: Mandell GL, Bennett JE, Dolin R, editors. Principles and Practice of Infectious Diseases. Philadelphia: Churchill Livingstone Elsevier; 2005. p. 2060-85.
  28. Oliveira EC, Marik PE, Colice G. Influenza pneumonia: A descriptive study. Chest 2001;119:1717-23.
  29. Chien YS, Su CP, Tsai HT, Huang AS, Lien CE, Hung MN, et al. Predictors and outcomes of respiratory failure among hospitalized pneumonia patients with 2009 H1N1 influenza in Taiwan. J Infect 2010;60:168-74.
  30. Auyeung TW, Lee JS, Lai WK, Choi CH, Lee HK, Lee JS, et al. The use of corticosteroid as treatment in SARS was associated with adverse outcomes: A retrospective cohort study. J Infect 2005;51:98-102.
  31. Shlomai A, Nutman A, Kotlovsky T, Schechner V, Carmeli Y, Guzner-Gur H. Predictors of pandemic (H1N1) 2009 virus positivity and adverse outcomes among hospitalized patients with a compatible syndrome. Isr Med Assoc J 2010;12:622-7.
  32. Liem NT, Tung CV, Hien ND, Hien TT, Chau NQ, Long HT, et al. Clinical features of human influenza A (H5N1) infection in Vietnam: 2004-2006. Clin Infect Dis 2009;48:1639-46.
  33. WHO Guidelines for Pharmacological Management of Pandemic Influenza A (H1N1) 2009 and Other Influenza Viruses. Geneva: World Health Organization; 2010. Available from: [Last accessed on 2010 Feb].
  34. Writing Committee of the WHO Consultation on Clinical Aspects of Pandemic (H1N1) 2009 Influenza, Bautista E, Chotpitayasunondh T, Gao Z, Harper SA, Shaw M, et al. Clinical aspects of pandemic 2009 influenza A (H1N1) virus infection. N Engl J Med 2010;362:1708-19.
  35. Updated interim recommendations for the use of antiviral medications in the treatment and prevention of influenza for the 2009-2010 season. Atlanta: Centers for Disease Control and Prevention; 2009. Available from: [Last accessed on 2011 Mar 10].
  36. McGeer A, Green KA, Plevneshi A, Shigayeva A, Siddiqi N, Raboud J, et al. Antiviral therapy and outcomes of influenza requiring hospitalization in Ontario, Canada. Clin Infect Dis 2007;45:1568-75.
  37. Chacko J, Gagan B, Ashok E, Radha M, Hemanth HV. Critically ill patients with 2009 H1N1 infection in an Indian ICU. Indian J Crit Care Med 2010;14:77-82.
  38. Chudasama RK, Verma PB, Amin CD, Gohel B, Savariya D, Ninama R. Correlates of severe disease in patients admitted with 2009 pandemic influenza A (H1N1) infection in Saurashtra region, India. Indian J Crit Care Med 2010;14:113-20.
  39. Sahoo JN, Poddar B, Azim A, Singh RK, Gurjar M, Baronia AK. Pandemic (H1N1) 2009 influenza: Experience from a critical care unit in India. Indian J Crit Care Med 2010;14:156-9.
PDF Share
PDF Share

© Jaypee Brothers Medical Publishers (P) LTD.