Abstract
Objectives: Although the increased risk of hospitalization and mortality during influenza seasons has been documented extensively, there is a relative paucity of research on the impact of influenza-related illnesses on other health care use indicators, such as physician use. The purpose of this study was to examine the impact of influenza-associated respiratory illnesses on the Winnipeg health care system, including hospitalizations, physician visits and emergency room visits. Their impact on mortality was also examined.
Methods: Administrative data were used to track health care use and mortality over four influenza seasons (1995–96 to 1998–99). Excess health care use and deaths were calculated by subtracting rates during influenza seasons from those during weeks when influenza viruses were not circulating.
Results: Significant excess hospitalization, physician visit, and emergency room visit rates emerged for influenza and pneumonia, acute respiratory diseases, and chronic lung disease, especially among children and adults aged 65 and over. Considerable excess mortality due to influenza and pneumonia and chronic lung disease among individuals aged 65 and over also emerged, particularly among nursing home residents.
Discussion: Influenza-associated respiratory illnesses have a substantial impact on the health care system. Given the burden of illness among children during influenza seasons, the study further suggests that influenza vaccination might be considered for this age group.
Résumé
Objectifs: Les risques accrus d’hospitalisation et de mortalité durant la saison grippale sont bien documentés, mais les études sur les incidences des maladies liées à la grippe sur d’autres indicateurs de l’utilisation des soins de santé, comme le recours aux médecins, sont encore relativement rares. On examine ici les incidences des maladies respiratoires associées à la grippe sur le système de soins de santé de Winnipeg (hospitalisations, visites chez le médecin et visites aux salles d’urgence). On examine aussi leurs incidences sur la mortalité.
Méthode: À l’aide de données administratives, on a suivi l’utilisation des soins de santé et la mortalité sur quatre saisons grippales (1995–1996 à 1998–1999). La surutilisation des soins de santé et la surmortalité ont été calculées en soustrayant les taux durant les saisons grippales des taux durant les semaines où les virus de la grippe ne circulaient pas.
Résultats: La grippe, la pneumonie, les maladies respiratoires aiguës et les pneumopathies chroniques ont causé d’importants excédents dans les taux d’hospitalisation et les visites chez le médecin et dans les salles d’urgence, surtout pour les enfants et les adultes de 65 ans et plus. Une importante surmortalité due à la grippe, à la pneumonie et aux pneumopathies a aussi été enregistrée chez les 65 ans et plus, tout particulièrement parmi les pensionnaires de maisons de soins infirmiers.
Débat: Les maladies respiratoires associées à la grippe ont de graves répercussions sur le système de soins de santé. Comme les enfants tombent souvent malades durant la saison grippale, on recommande aussi d’envisager de les vacciner contre la grippe.
Footnotes
Acknowledgements: This research resulted from a project undertaken for Manitoba Health by the Manitoba Centre for Health Policy. The project was funded by Manitoba Health. The results and conclusions are those of the authors, and no official endorsement by Manitoba Health is intended or should be inferred. The authors thank Health Information Services, Manitoba Health, and the Office of Vital Statistics in the Agency of Consumer and Corporate Affairs for the provision of data. Dr. Menec holds a New Investigator Career award from the Canadian Institutes of Health Research.
References
- 1.Canadian Consensus Conference on Influenza. Can Commun Dis Rep. 1993;19:136–47. [PubMed] [Google Scholar]
- 2.Statistics Canada. Selected Leading Causes of Death by Sex, Canada, 1995. Ottawa: Statistics Canada, Health Statistics Division; 1997. [Google Scholar]
- 3.Glezen W, Couch R. Interpandemic influenza in the Houston area, 1974–76. N Engl J Med. 1978;298:587–92. doi: 10.1056/NEJM197803162981103. [DOI] [PubMed] [Google Scholar]
- 4.Tillett HE, Smith JW, Clifford RE. Excess morbidity and mortality associated with influenza in England and Wales. Lancet. 1980;1:793–95. doi: 10.1016/S0140-6736(80)91293-3. [DOI] [PubMed] [Google Scholar]
- 5.Barker WH, Mullooly JP. Pneumonia and influenza deaths during epidemics. Arch Intern Med. 1982;142:85–89. doi: 10.1001/archinte.1982.00340140087016. [DOI] [PubMed] [Google Scholar]
- 6.Choi K, Thacker SB. Mortality during influenza epidemics in the United States, 1967–1978. Am J Public Health. 1982;72:1280–83. doi: 10.2105/AJPH.72.11.1280. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7.Glezen PW. Serious morbidity and mortality associated with influenza epidemics. Epidemiol Rev. 1982;4:24–44. doi: 10.1093/oxfordjournals.epirev.a036250. [DOI] [PubMed] [Google Scholar]
- 8.Perrotta DM, Decker M, Glezen WP. Acute respiratory disease hospitalization as a measure of impact of epidemic influenza. Am J Epidemiol. 1985;122:468–76. doi: 10.1093/oxfordjournals.aje.a114128. [DOI] [PubMed] [Google Scholar]
- 9.Barker WH. Excess pneumonia and influenza associated hospitalization during influenza epidemics in the Unites States, 1970–78. Am J Public Health. 1986;76:761–65. doi: 10.2105/AJPH.76.7.761. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10.Lui K, Kendal AP. Impact of influenza epidemics on mortality in the United States from October 1972 to May 1985. Am J Public Health. 1987;77:712–16. doi: 10.2105/AJPH.77.6.712. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.McBean AM, Babish JD, Warren JL. The impact and cost of influenza in the elderly. Arch Intern Med. 1993;153:2105–11. doi: 10.1001/archinte.1993.00410180051005. [DOI] [PubMed] [Google Scholar]
- 12.Glezen WP. Epidemic influenza. Epidemiol Rev. 1996;18:64–76. doi: 10.1093/oxfordjournals.epirev.a017917. [DOI] [PubMed] [Google Scholar]
- 13.Baltussen RM, Reinders A, Sprenger MJW, Postma MJ, Jager JC, Ament AJ, et al. Estimating influenza-related hospitalization in the Netherlands. Epidemiol Infect. 1998;121:129–38. doi: 10.1017/S0950268898008966. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 14.Neuzil KM, Reed GW, Mitchell EF, Griffin MR. Influenza-associated morbidity and mortality in young and middle-aged women. JAMA. 1999;281:901–7. doi: 10.1001/jama.281.10.901. [DOI] [PubMed] [Google Scholar]
- 15.Upshur REG, Knight K, Goel V. Time-series analysis of the relation between influenza virus and hospital admissions of the elderly in Ontario, Canada, for pneumonia, chronic lung disease, and congestive heart failure. Am J Epidemiol. 1999;149:85–92. doi: 10.1093/oxfordjournals.aje.a009731. [DOI] [PubMed] [Google Scholar]
- 16.Izurieta HS, Thompson WW, Kramarz P, Shay DK, Davis RL, DeStefano F, et al. Influenza and the rates of hospitalization for respiratory disease among infants and young children. N Engl J Med. 2000;342:232–39. doi: 10.1056/NEJM200001273420402. [DOI] [PubMed] [Google Scholar]
- 17.Neuzil KM, Mellen BG, Wright PF, Mitchell EF, Griffin MR. The effect of influenza on hospitaliza-tions, outpatient visits and courses of antibiotics in children. N Engl J Med. 2000;342:225–31. doi: 10.1056/NEJM200001273420401. [DOI] [PubMed] [Google Scholar]
- 18.Simonson L, Fukuda K. The impact of influenza epidemics on hospitalizations. J Infect Dis. 2000;181:831–37. doi: 10.1086/315320. [DOI] [PubMed] [Google Scholar]
- 19.Upshur REG, Goel V. Measuring the impact of influenza on the hospital admission rates of the elderly in Ontario: A five-year admission rate analysis, 1988–1993. Can J Public Health. 2000;91:144–47. doi: 10.1007/BF03404931. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 20.Fleming DM, Zambon M, Bartelds AIM. Population estimates of persons presenting to general practitioners with influenza-like illness, 1987-96: A study of the demography of influenza-like illness in sentinel practice networks in England and Wales, and in the Netherlands. Epidemiol Infect. 2000;124:245–53. doi: 10.1017/S0950268899003660. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 21.Nichol KL, Margolis KL, Wuorenma J, von Sternberg T. The efficacy and cost effectiveness of vaccination against influenza among elderly persons living in the community. N Engl J Med. 1994;331:778–84. doi: 10.1056/NEJM199409223311206. [DOI] [PubMed] [Google Scholar]
- 22.Nichol KL, Wourenma J, von Sternberg T. Benefits of influenza vaccination for low-, intermediate-, and high-risk senior citizens. Arch Intern Med. 1998;158:1769–76. doi: 10.1001/archinte.158.16.1769. [DOI] [PubMed] [Google Scholar]
- 23.Barer ML, Sheps SB, Mustard C, Kasian P. Emergency Room Use in Winnipeg Hospitals, 1991-92. Winnipeg: Manitoba Health; 1994. [Google Scholar]
- 24.Gross PA, Hermogenes AW, Sacks HS, Lau J, Levandowski RA. The efficacy of influenza vaccine in elderly persons: A meta-analysis and review of the literature. Ann Intern Med. 1995;123:518–27. doi: 10.7326/0003-4819-123-7-199510010-00008. [DOI] [PubMed] [Google Scholar]
- 25.National Advisory Committee on Immunization. Statement on influenza vaccination for the 1999–2000 season. Can Commun Dis Rep. 1999;25:1–13. [PubMed] [Google Scholar]
- 26.Manitoba Health. Manitoba’s Health Indicators Report. Winnipeg: Manitoba Health; 2002. [Google Scholar]