摘要：Objectives. We compared seasonal influenza hospital use among older adults in long-term care (LTC) and community settings. Methods. We used provincial administrative data from Ontario to identify all emergency department (ED) visits and hospital admissions for pneumonia and influenza among adults older than 65 years between 2002 and 2008. We used sentinel laboratory reports to define influenza and summer seasons and estimated mean annual event rates and influenza-associated rates. Results. Mean annual pneumonia and influenza ED visit rates were higher in LTC than the community (rate ratio [RR] for influenza season = 3.9; 95% confidence interval [CI] = 3.8, 4.0; for summer = 4.9; 95% CI = 4.8, 5.1) but this was attenuated in influenza-associated rates (RR = 2.4; 95% CI = 2.1, 2.8). The proportion of pneumonia and influenza ED visits attributable to seasonal influenza was 17% (15%–20%) in LTC and 28% (27%–29%) in the community. Results for hospital admissions were comparable. Conclusions. We found high rates of hospital use from LTC but evidence of lower impact of circulating influenza in the community. This differential impact of circulating influenza between the 2 environments may result from different influenza control policies. Influenza has been identified as among the top 10 infectious agents that are causes of health burden, 1 and it continues to create significant morbidity and mortality among older adults. Individuals older than 65 years, in particular those with preexisting chronic conditions, are at increased risk for hospitalization 2,3 and death 4,5 associated with influenza. The Canadian province of Ontario first introduced universal influenza immunization in 2000, granting all provincial residents aged 6 months or older the option for annual immunization without out-of-pocket cost. Although immunization coverage in the general population remains relatively low, levels are highest among community-dwelling adults older than 65 years, with coverage exceeding 70%. 6 For residents of long-term care (LTC) facilities, also known as nursing homes, immunization coverage generally exceeds 90% in Ontario 7 and 80% in other jurisdictions, mainly because of concerted efforts to reach this group. 8,9 LTC residents are a particularly vulnerable segment of the older population, with an average age of 80 years, significant cognitive and physical impairments, and a high burden of complex chronic conditions, including cardiovascular and respiratory illnesses. Despite high immunization coverage in residents, influenza continues to cause significant burden. Influenza has been associated with increased rates of functional decline and pressure ulcers in this group. 10 It is also among the most common reasons for transfer to the hospital and accounts for a significant proportion of mortality in this population. 11–13 A single study reported that rates of hospitalization for influenza were 3 times as high among LTC as among community residents, both during and before the identified influenza season. 14 In addition to their heightened vulnerability, LTC residents face other risk factors for infection, including congregate living and shared bedrooms, that community residents do not experience. Because of this, LTC is targeted for strong infection prevention and control (IPC) measures, including staff immunization. Although evidence from Ontario suggests that LTC staff immunization rates are generally higher than 70%, 7 well above that reported in hospitals, other evidence points to generally poor compliance with other IPC practices. 15 To date, little is known about the burden of influenza in LTC and how it compares to that in the community. Our objectives were to compare the burden of influenza, as measured by hospital use, both emergency department (ED) visits and inpatient admissions, among older adults in LTC and community settings.
