High Utilizers of Emergency Health Services in a Population-Based Cohort of Homeless Adults

摘要

Objectives. We identified predictors of emergency department (ED) use among a population-based prospective cohort of homeless adults in Toronto, Ontario. Methods. We assessed ED visit rates using administrative data from the Institute for Clinical Evaluative Sciences (2005–2009). We then used logistic regression to identify predictors of ED use. Frequent users were defined as participants with rates in the top decile (≥?4.7 visits per person-year). Results. Among 1165 homeless adults, 892 (77%) had at least 1 ED visit during the study. The average rate of ED visits was 2.0 visits per person-year, whereas frequent users averaged 12.1 visits per person-year. Frequent users accounted for 10% of the sample but contributed more than 60% of visits. Predictors of frequent use in adjusted analyses included birth in Canada, higher monthly income, lower health status, perceived unmet mental health needs, and perceived external health locus of control from powerful others; being accompanied by a partner or dependent children had a protective effect on frequent use. Conclusions. Among homeless adults with universal health insurance, a small subgroup accounted for the majority of visits to emergency services. Frequent use was driven by multiple predisposing, enabling, and need factors. Frequent emergency department (ED) use among homeless persons has been the subject of research studies 1–5 and high-profile media attention. 6–8 These articles highlight the significant burden placed on the health care system from frequent emergency health care use in terms of economic costs, poor patient outcomes, treatment delays, and lower quality of care. 9,10 For example, in a nationwide US study, homeless adults were 3 times more likely to have repeat ED visits and were more than twice as likely to return to the ED after hospitalization compared with nonhomeless people. 1 Homeless adults contributed an estimated 0.5% of total ED visits across the United States but represent only 0.25% of the general population. 1 Frequent health care utilization among homeless persons may be the result of an increased need for emergency health services. 2,11–14 Homeless people experience disproportionately high rates of chronic and acute health conditions and traumatic injuries and assaults. 15,16 Substance use and mental illness are also highly prevalent. 1–4,17 However, the increased use of emergency services may also be an indicator of lack of access to primary health care in ambulatory settings, 17–21 often in the presence of competing priorities for basic subsistence needs. 22 These factors may increase the need for emergency services because of potentially preventable deteriorations in health status. 2,23 According to the Behavioral Model of Health Services Utilization for Vulnerable Populations, 24 determinants of health care use can be grouped into predisposing factors (i.e., demographic characteristics and social structural attributes that affect the propensity to use services), enabling factors (i.e., personal, family, and community resources that facilitate the use of services), and need factors (i.e., symptoms or health conditions that precipitate health service use). We undertook this prospective cohort study to identify predictors of frequent ED use among a population-based sample of homeless adults in Toronto, Ontario. We examined these predictors within a framework of the Behavioral Model of Health Services Utilization for Vulnerable Populations. 24 This phenomenon was difficult to study using administrative data in the United States, where more than one-half of homeless people lack any form of health insurance. 17 Most US studies rely on self-reported data 2,17,25,26 or restrict their analysis to a single health care institution. 1,3 This study had the unique advantage of being able to accurately quantify health care use among homeless adults using a population-based approach in a setting where all individuals have access to universal health insurance and all ED visits for the province are recorded in a single administrative database. Using these administrative databases, this study was also able to compare rates of ED use among homeless participants to age- and gender-matched, low-income population controls.