The impact of influenza A(H1N1)pdm09 compared with seasonal influenza on intensive care admissions in New South Wales, Australia, 2007 to 2010: a time series analysis

BMC Public Health

James Ward¹  Sean Tobin²  Robin Gilmour²  Michelle Cretikos³  David Muscatello³  Andrea Schaffer³ 

[1] Aboriginal and Torres Strait Islander Health Program, Kirby Institute, Sydney, NSW, Australia;Centre for Health Protection, NSW Ministry of Health, North Sydney, NSW, Australia;Centre for Epidemiology and Research, NSW Ministry of Health, North Sydney, NSW, Australia

关键词: Pregnancy;    Indigenous;    Demand;    Pandemic;    Australia;    H1N1;    Hospitalisations;    Respiratory illness;    Influenza;    Intensive care;   

Others  :  1162981
DOI  :  10.1186/1471-2458-12-869

 received in 2012-04-20, accepted in 2012-10-10,  发布年份 2012

【 摘 要 】

Background

In Australia, the 2009 epidemic of influenza A(H1N1)pdm09 resulted in increased admissions to intensive care. The annual contribution of influenza to use of intensive care is difficult to estimate, as many people with influenza present without a classic influenza syndrome and laboratory testing may not be performed. We used a population-based approach to estimate and compare the impact of recent epidemics of seasonal and pandemic influenza.

Methods

For 2007 to 2010, time series describing health outcomes in various population groups were prepared from a database of all intensive care unit (ICU) admissions in the state of New South Wales, Australia. The Serfling approach, a time series method, was used to estimate seasonal patterns in health outcomes in the absence of influenza epidemics. The contribution of influenza was estimated by subtracting expected seasonal use from observed use during each epidemic period.

Results

The estimated excess rate of influenza-associated respiratory ICU admissions per 100,000 inhabitants was more than three times higher in 2007 (2.6/100,000, 95% CI 2.0 to 3.1) than the pandemic year, 2009 (0.76/100,000, 95% CI 0.04 to 1.48). In 2009, the highest excess respiratory ICU admission rate was in 17 to 64 year olds (2.9/100,000, 95% CI 2.2 to 3.6), while in 2007, the highest excess rate was in those aged 65 years or older (9.5/100,000, 95% CI 6.2 to 12.8). In 2009, the excess rate was 17/100,000 (95% CI 14 to 20) in Aboriginal people and 14/100,000 (95% CI 13 to 16) in pregnant women.

Conclusion

While influenza was diagnosed more frequently and peak use of intensive care was higher during the epidemic of pandemic influenza in 2009, overall excess admissions to intensive care for respiratory illness was much greater during the influenza season in 2007. Thus, the impact of seasonal influenza on intensive care use may have previously been under-recognised. In 2009, high ICU use among young to middle aged adults was offset by relatively low use among older adults, and Aboriginal people and pregnant women were substantially over-represented in ICUs. Greater emphasis on prevention of serious illness in Aboriginal people and pregnant women should be a priority in pandemic planning.

【 授权许可】

   
2012 Schaffer et al.; licensee BioMed Central Ltd.

【 图 表 】

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【 参考文献 】

• [1]Webb SA, Pettila V, Seppelt I, Bellomo R, Bailey M, Cooper DJ, Cretikos M, Davies AR, Finfer S, Harrigan PW, et al.: Critical care services and 2009 H1N1 influenza in Australia and New Zealand. New Engl J Med 2009, 361(20):1925-1934.
• [2]Lum ME, McMillan AJ, Brook CW, Lester R, Piers LS: Impact of pandemic (H1N1) 2009 influenza on critical care capacity in Victoria. Med J Australia 2009, 191(9):502-506.
• [3]New South Wales Public Health Network: Progression and impact of the first winter wave of the 2009 pandemic H1N1 influenza in New South Wales, Australia. Euro Surveill 2009, 14:42.
• [4]Centers for Disease Control and Prevention (CDC): Intensive-care patients with severe novel influenza A (H1N1) virus infection - Michigan, June 2009. MMWR Morb Mortal Wkly Rep 2009, 58(27):749-752.
• [5]Kumar A, Zarychanski R, Pinto R, Cook DJ, Marshall J, Lacroix J, Stelfox T, Bagshaw S, Choong K, Lamontagne F, et al.: Critically ill patients with 2009 influenza A(H1N1) infection in Canada. JAMA 2009, 302(17):1872-1879.
• [6]Rello J, Rodriguez A, Ibanez P, Socias L, Cebrian J, Marques A, Guerrero J, Ruiz-Santana S, Marquez E, Del Nogal-Saez F, et al.: Intensive care adult patients with severe respiratory failure caused by Influenza A (H1N1)v in Spain. Crit Care 2009, 13(5):R148. BioMed Central Full Text
• [7]Louie JK, Acosta M, Jamieson DJ, Honein MA: Severe 2009 H1N1 influenza in pregnant and postpartum women in California. New Engl J Med 2010, 362(1):27-35.
• [8]Chowell G, Bertozzi SM, Colchero MA, Lopez-Gatell H, Alpuche-Aranda C, Hernandez M, Miller MA: Severe respiratory disease concurrent with the circulation of H1N1 influenza. New Engl J Med 2009, 361(7):674-679.
• [9]Davies A, Jones D, Bailey M, Beca J, Bellomo R, Blackwell N, Forrest P, Gattas D, Granger E, Herkes R, et al.: Extracorporeal Membrane Oxygenation for 2009 Influenza A(H1N1) Acute Respiratory Distress Syndrome. JAMA 2009, 302(17):1888-1895.
• [10]Babcock HM, Merz LR, Fraser VJ: Is influenza an influenza-like illness? Clinical presentation of influenza in hospitalized patients. Infect Control Hosp Epidemiol 2011, 32:1055.
• [11]Kuster SP, Katz KC, Blair J, Downey J, Drews SJ, Finkelstein S, Fowler R, Green K, Gubbay J, Hassan K, et al.: When should a diagnosis of influenza be considered in adults requiring intensive care unit admission? Results of population-based active surveillance in Toronto. Crit Care 2011, 15:R182. BioMed Central Full Text
• [12]Newall AT, Wood JG, Macintyre CR: Influenza-related hospitalisation and death in Australians aged 50 years and older. Vaccine 2008, 26(17):2135-2141.
• [13]Thompson WW, Shay DK, Weintraub E, Brammer L, Bridges CB, Cox NJ, Fukuda K: Influenza-associated hospitalizations in the United States. JAMA 2004, 292(11):1333-1340.
• [14]Australian Bureau of Statistics (ABS): 3235.0 - Population by Age and Sex, Regions of Australia. 2010. http://www.abs.gov.au/AUSSTATS/abs@.nsf/DetailsPage/3235.02010?OpenDocument webcite.
• [15]Australian Bureau of Statistics (ABS): 3238.0 - Experimental estimates and projections: Aboriginal and Torres Strait Islander Australians. 1991 to 2021. http://www.abs.gov.au/AUSSTATS/abs@.nsf/DetailsPage/3238.01991%20to%202021?OpenDocument webcite.
• [16]Australian Bureau of Statistics (ABS): 3301.0 - Births, Australia. 2009. http://www.abs.gov.au/AUSSTATS/abs@.nsf/DetailsPage/3301.02009?OpenDocument webcite.
• [17]Serfling RE: Methods for current statistical analysis of excess pneumonia-influenza deaths. Public Health Rep 1963, 78(6):494-506.
• [18]Muscatello DJ, Cretikos MA, Macintyre CR: All-cause mortality during first wave of pandemic (H1N1) 2009, New South Wales, Australia, 2009. Emerg Infect Dis 2010, 16(9):1396-1402.
• [19]Armstrong GL, Brammer L, Finelli L: Timely assessment of the severity of the 2009 H1N1 influenza pandemic. Clin Infect Dis 2011, 52(Suppl 1):S83-S89.
• [20]Babcock HM, Merz LR, Dubberke ER, Fraser VJ: Case–control study of clinical features of influenza in hospitalized patients. Infect Control Hosp Epidemiol 2008, 29(10):921-926.
• [21]van den Dool C, Hak E, Wallinga J, van Loon AM, Lammers JW, Bonten MJ: Symptoms of influenza virus infection in hospitalized patients. Infect Control Hosp Epidemiol 2008, 29(4):314-319.
• [22]Owen R, Barr IG, Pengilley A, Liu C, Paterson B, Kaczmarek M: Annual report of the National Influenza Surveillance Scheme, 2007. Commun Dis Intell 2008, 32(2):208-226.
• [23]Booy R, Khandaker G, Heron LG, Yin J, Doyle B, Tudo KK, Hueston L, Gilbert GL, Macintyre CR, Dwyer DE: Cross-reacting antibodies against the pandemic (H1N1) 2009 influenza virus in older Australians. Med J Australia 2011, 194(1):19-23.
• [24]Gilbert GL, Cretikos MA, Hueston L, Doukas G, O'Toole B, Dwyer DE: Influenza A (H1N1) 2009 antibodies in residents of New South Wales, Australia, after the first pandemic wave in the 2009 southern hemisphere winter. PLoS One 2010, 5(9):e12562.
• [25]Hancock K, Veguilla V, Lu X, Zhong W, Butler EN, Sun H, Liu F, Dong L, DeVos JR, Gargiullo PM, et al.: Cross-reactive antibody responses to the 2009 pandemic H1N1 influenza virus. New Engl J Med 2009, 361(20):1945-1952.
• [26]Widgren K, Nielsen J, Molbak K: Registry-based surveillance of influenza-associated hospitalisations during the 2009 influenza pandemic in Denmark: the hidden burden on the young. PLoS One 2011, 5:e13939.
• [27]Murata Y, Walsh EE, Falsey AR: Pulmonary complications of interpandemic influenza A in hospitalized adults. J Infect Dis 2007, 195(7):1029-1037.
• [28]Flint SM, Davis JS, Su JY, Oliver-Landry EP, Rogers BA, Goldstein A, Thomas JH, Parameswaran U, Bigham C, Freeman K, et al.: Disproportionate impact of pandemic (H1N1) 2009 influenza on Indigenous people in the Top End of Australia's Northern Territory. Med J Australia 2010, 192(10):617-622.
• [29]La Ruche G, Tarantola A, Barboza P, Vaillant L, Gueguen J, Gastellu-Etchegorry M: The 2009 pandemic H1N1 influenza and indigenous populations of the Americas and the Pacific. Euro Surveill 2009, 14:42.
• [30]Kelly H, Mercer G, Cheng A: Quantifying the risk of pandemic influenza in pregnancy and indigenous people in Australia in 2009. Euro Surveill 2009, 14:50.
• [31]Campbell A, Rodin R, Kropp R, Mao Y, Hong Z, Vachon J, Spika J, Pelletier L: Risk of severe outcomes among patients admitted to hospital with pandemic (H1N1) influenza. CMAJ 2010, 182(4):349-355.
• [32]Goggin LS, Carcione D, Mak DB, Dowse GK, Giele CM, Smith DW, Effler PV: Chronic disease and hospitalisation for pandemic (H1N1) 2009 influenza in Indigenous and non-Indigenous Western Australians. Commun Dis Intell 2011, 35(2):172-176.
• [33]Thompson WW, Weintraub E, Dhankhar P, Cheng PY, Brammer L, Meltzer MI, Bresee JS, Shay DK: Estimates of US influenza-associated deaths made using four different methods. Influenza Other Respi Viruses 2009, 3(1):37-49.
• [34]Newall AT, Viboud C, Wood JG: Influenza-attributable mortality in Australians aged more than 50 years: a comparison of different modelling approaches. Epidemiol Infect 2010, 138(6):836-842.
• [35]Sandoval C, Walter SD, Krueger P, Loeb MB: Comparing estimates of influenza-associated hospitalization and death among adults with congestive heart failure based on how influenza season is defined. BMC Public Health 2008, 8:59-65. BioMed Central Full Text
• [36]Bishop JF, Murnane MP, Owen R: Australia's winter with the 2009 pandemic influenza A (H1N1) virus. N Engl J Med 2009, 361:2591-2594.
• [37]Poole PJ, Chacko E, Wood-Baker RW, Cates CJ: Influenza vaccine for patients with chronic obstructive pulmonary disease. Cochrane Database Syst Rev 2006, 1:CD002733.