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The Role of Charity Care and Primary Care Physician Assignment on ED Use in Homeless Patients

Open AccessPublished:April 20, 2015DOI:https://doi.org/10.1016/j.ajem.2015.04.026

      Abstract

      Objective

      Homeless patients are a vulnerable population with a higher incidence of using the emergency department (ED) for noncrisis care. Multiple charity programs target their outreach toward improving the health of homeless patients, but few data are available on the effectiveness of reducing ED recidivism. The aim of this study is to determine whether inappropriate ED use for nonemergency care may be reduced by providing charity insurance and assigning homeless patients to a primary care physician (PCP) in an outpatient clinic setting.

      Methods

      A retrospective medical records review of homeless patients presenting to the ED and receiving treatment between July 2013 and June 2014 was completed. Appropriate vs inappropriate use of the ED was determined using the New York University ED Algorithm. The association between patients with charity care coverage, PCP assignment status, and appropriate vs inappropriate ED use was analyzed and compared.

      Results

      Following New York University ED Algorithm standards, 76% of all ED visits were deemed inappropriate with approximately 77% of homeless patients receiving charity care and 74% of patients with no insurance seeking noncrisis health care in the ED (P = .112). About 50% of inappropriate ED visits and 43.84% of appropriate ED visits occurred in patients with a PCP assignment (P = .019).

      Conclusions

      Both charity care homeless patients and those without insurance coverage tend to use the ED for noncrisis care resulting in high rates of inappropriate ED use. Simply providing charity care and/or PCP assignment does not seem to sufficiently reduce inappropriate ED use in homeless patients.

      1. Introduction

      Compared with nonhomeless patients, homeless patients are a special population with more barriers to appropriate access to preventive health care services such as personal, bureaucratic, programmatic, and financial factors [
      • Hoshide R.R.
      • Manog J.D.
      • Noh T.
      • Omori J.
      Barriers to healthcare of homeless residents of three Honolulu shelters.
      ,
      • Tankimovich M.
      Barriers to and interventions for improved tuberculosis detection and treatment among homeless and immigrant populations: a literature review.
      ]. As such, these patients tend to inappropriately use the emergency department (ED) more often than the general population [
      • Hwang S.W.
      • Chambers C.
      • Chiu S.
      • Katic M.
      • Kiss A.
      • Redelmeier D.A.
      • et al.
      A comprehensive assessment of health care utilization among homeless adults under a system of universal health insurance.
      ,
      • Levy B.D.
      • O'Connell J.J.
      Health care for homeless persons.
      ,
      • Tsai J.
      • Doran K.M.
      • Rosenheck R.A.
      When health insurance is not a factor: national comparison of homeless and nonhomeless US veterans who use Veterans Affairs Emergency Departments.
      ]. Inappropriate ED use is operationally defined as those patients who present with clinical signs and symptoms that are categorized as nonurgent and could be handled in a nonemergent manner such as in a primary care physician (PCP) clinic. Anecdotal evidence in our ED in Texas and the empirical evidence from other studies show that homeless patients tend to be high ED users [
      • Hwang S.W.
      • Chambers C.
      • Chiu S.
      • Katic M.
      • Kiss A.
      • Redelmeier D.A.
      • et al.
      A comprehensive assessment of health care utilization among homeless adults under a system of universal health insurance.
      ,
      • Levy B.D.
      • O'Connell J.J.
      Health care for homeless persons.
      ,
      • Coe A.B.
      • Moczygemba L.R.
      • Harpe S.E.
      • Gatewood S.B.
      Homeless patients' use of urban emergency departments in the United States.
      ]. They are older, more often male, and their visits tend to result in a higher rate of hospitalization [
      • Coe A.B.
      • Moczygemba L.R.
      • Harpe S.E.
      • Gatewood S.B.
      Homeless patients' use of urban emergency departments in the United States.
      ]. A tendency toward inappropriate ED use by homeless patients is documented in the literature in association with ED overcrowding resulting in negative prognostic outcomes [
      • de Araujo P.
      • Khraiche M.
      • Tukan A.
      Does overcrowding and health insurance type impact patient outcomes in emergency departments?.
      ,
      • Hoot N.R.
      • Aronsky D.
      Systematic review of emergency department crowding: causes, effects, and solutions.
      ].
      The New York University ED Algorithm (NYUA) has been commonly used to identify an appropriate level of ED use with consistently high accuracy as reported by previous studies [
      • Gandhi S.O.
      • Grant L.P.
      • Sabik L.M.
      Trends in nonemergent use of emergency departments by health insurance status.
      ,
      • Ballard D.W.
      • Price M.
      • Fung V.
      • Brand R.
      • Reed M.E.
      • Fireman B.
      • et al.
      Validation of an algorithm for categorizing the severity of hospital emergency department visits.
      ]. It classifies ED visits into different categories based on patients’ ages, chief complaints, and their vital signs. Appropriate ED use is defined as a visit that is within an emergent nonavoidable category, whereas inappropriate ED use refers to an ED visit that is emergent yet avoidable. By definition, inappropriate ED use includes illnesses or injuries that are primary care treatable, ED preventable/avoidable, or nonemergent categories. However, until now, the application of the NYUA to determine appropriateness of ED use among homeless patients has rarely been reported and thus requires further investigation [
      • Begley C.E.
      • Vojvodic R.W.
      • Seo M.
      • Burau K.
      Emergency room use and access to primary care: evidence from Houston, Texas.
      ].
      Meanwhile, multiple charity programs providing PCP clinic access and charity insurance coverage to homeless patients have been examined as mediating factors in minimizing inappropriate ED use [
      • Capp R.
      • Rosenthal M.S.
      • Desai M.M.
      • Kelley L.
      • Borgstrom C.
      • Cobbs-Lomax D.L.
      • et al.
      Characteristics of Medicaid enrollees with frequent ED use.
      ,
      • Chwastiak L.
      • Tsai J.
      • Rosenheck R.
      Impact of health insurance status and a diagnosis of serious mental illness on whether chronically homeless individuals engage in primary care.
      ,
      • Bharel M.
      • Lin W.C.
      • Zhang J.
      • O'Connell E.
      • Taube R.
      • Clark R.E.
      Health care utilization patterns of homeless individuals in Boston: preparing for Medicaid expansion under the Affordable Care Act.
      ,
      • Hookey S.J.
      StreetHealth - improving access to primary care.
      ,
      • Weber M.
      • Thompson L.
      • Schmiege S.J.
      • Peifer K.
      • Farrell E.
      Perception of access to health care by homeless individuals seeking services at a day shelter.
      ,
      • Schoon P.M.
      • Champlin B.E.
      • Hunt R.J.
      Developing a sustainable foot care clinic in a homeless shelter within an academic-community partnership.
      ]. Providing charity insurance coverage to the homeless is one supporting program that simply furnishes health care insurance coverage to this population with very low or no cost paid by the patients. In addition, their monthly insurance premiums usually are waived as well. Considering the potential risk of homeless patients unable to access PCP clinics without copay resources or insurance coverage, providing charity insurance theoretically minimizes inappropriate ED use among these patients. Some studies reported that providing charity insurance can decrease inappropriate ED use. Lack of health insurance that usually refers to self-paid homeless patients was strongly associated with inappropriate ED use in several studies, whereas other studies showed little or no association [
      • Hwang S.W.
      • Chambers C.
      • Chiu S.
      • Katic M.
      • Kiss A.
      • Redelmeier D.A.
      • et al.
      A comprehensive assessment of health care utilization among homeless adults under a system of universal health insurance.
      ,
      • Capp R.
      • Rosenthal M.S.
      • Desai M.M.
      • Kelley L.
      • Borgstrom C.
      • Cobbs-Lomax D.L.
      • et al.
      Characteristics of Medicaid enrollees with frequent ED use.
      ,
      • Chwastiak L.
      • Tsai J.
      • Rosenheck R.
      Impact of health insurance status and a diagnosis of serious mental illness on whether chronically homeless individuals engage in primary care.
      ,
      • Bharel M.
      • Lin W.C.
      • Zhang J.
      • O'Connell E.
      • Taube R.
      • Clark R.E.
      Health care utilization patterns of homeless individuals in Boston: preparing for Medicaid expansion under the Affordable Care Act.
      ]. Similarly, providing PCP clinics to homeless patients has also been studied. However, these trials were more focused on providing mental health care and prescription medication services. The benefits of providing medical clinic care as an intervention to homeless patients is still questionable [
      • Hookey S.J.
      StreetHealth - improving access to primary care.
      ,
      • Weber M.
      • Thompson L.
      • Schmiege S.J.
      • Peifer K.
      • Farrell E.
      Perception of access to health care by homeless individuals seeking services at a day shelter.
      ,
      • Schoon P.M.
      • Champlin B.E.
      • Hunt R.J.
      Developing a sustainable foot care clinic in a homeless shelter within an academic-community partnership.
      ]. Taken together, it is still controversial as to whether providing charity insurance or PCP clinic access results in fewer inappropriate ED visits.
      Therefore, the aim of this study was to (1) investigate how often an inappropriate ED use occurs among homeless patients, (2) determine whether the inappropriate ED use was reduced when providing homeless patients with charity care insurance in comparison with patients with “no insurance,” and (3) examine whether patients assigned to a PCP clinic would continue inappropriate ED use.

      2. Methods

      2.1 Study population

      Homeless patients seeking ED care at our local publicly funded county hospital network were identified in our electronic health records (EHR) by using the keywords “homeless status” and pairing those positive queries with the Tarrant County Homeless Management Information System (HMIS) database archived in Fort Worth, TX, United States. The HMIS system contains personal information of individuals meeting the US Department of Housing and Urban Development definition of homelessness at the time of entry into the system. Each person entered into the HMIS is issued a card that entitles them access to homeless shelters and social services for a 12-month period. Individual HMIS information was matched with “homeless status” located in the EHR and verified using personal health information. When the data between the 2 data sets aligned, a flag was created and used to identify ED use. In addition to systematically flagging patients, the Care Connection for the Homeless team (CCHT) at the hospital had the ability to identify and flag patients who may have been missed because of data-matching issues or did not exist in the HMIS system. For situations where data were not matched between systems but homeless status was verified by CCHT, patients were flagged manually. There were also situations where patients may not have been in the HMIS system. This typically occurred when patients were homeless and unsheltered or not using those services requiring an HMIS card. These patients were also flagged manually by the CCHT if sufficient evidence of homeless status existed such as a certification letter from an outreach organization serving the homeless who validated their living situation.

      2.2 Study design

      After institutional review board approval was obtained, a retrospective chart review was conducted from July 1, 2013, through June 30, 2014, using the EHR of homeless patients who presented at the ED in our publicly funded, level I trauma center and teaching county hospital. The NYUA was used to objectively determine appropriate vs inappropriate ED use. Based on NYUA, 4 major categories were generated: (1) emergent not avoidable considered as ED appropriate visits, (2) primary care treatable defined as care that can be safely provided in a primary care setting without the need for emergent treatment, (3) emergent care needed but preventable/avoidable defined as patients whose disease conditions can be prevented/avoided if preventive care is received in a timely fashion, and (4) nonemergent. Appropriate ED use was considered if patients met the emergent not avoidable category criteria, and inappropriate use was determined if patients were classified within the other 3 categories. Accordingly, the records of homeless patients who were admitted to the hospital from the ED were considered as having used the ED appropriately per NYUA because of need for continued observation, evaluation, and treatment beyond that which is reasonably delivered in the ED. Therefore, these patients were excluded from this study. The records of homeless patients who were initially seen and then discharged from the ED were considered as potential inappropriate ED users and were eligible for review. We excluded ED visits that were unclassified or excluded by NYUA as well as those with a 50% risk of inappropriate ED use because of uncertainties and variations.
      Basic patient characteristics documented in this review included age, sex, race/ethnicity, ED diagnosis (International Classification of Diseases, Ninth Revision, codes), mode of arrival, status of PCP assignment, weekend vs weekday ED visits, total number of ED visits within the data collection period, and insurance type. Most patients whose charts were reviewed either had charity care or had no insurance coverage. Therefore, patients were divided into 2 groups based on their insurance status. In this study, homeless patients may qualify for different charity care insurance programs including Medicaid, local taxpayer sponsored, Amerigroup, Healthspring, and Wellcare programs. These patients were placed into the same group as those receiving charity care. Patients with self-pay status were considered under the no insurance coverage category. Patients who received Medicare, Veterans insurance, any commercial insurance, or were incarcerated wards of the city, county, or state were considered as receiving noncharity care insurance. Data analysis was focused on the comparisons among homeless patients with charity care insurance vs patients with no insurance coverage; thus, patients with noncharity care insurance were excluded from the final analysis. The basic demographics of homeless patients included in this study vs those excluded were also compared to determine whether population selection bias existed. The association between patients with charity care coverage, their PCP assignment, and their association with frequency of inappropriate use of the ED were also analyzed and compared. Frequency of ED use was further divided into 3 groups based upon the preliminary data analysis of homeless patients, expert opinion, and results from other studies [
      • Maizels M.
      Health resource utilization of the emergency department headache "repeater".
      ,
      • Chambers C.
      • Chiu S.
      • Katic M.
      • Kiss A.
      • Redelmeier D.A.
      • Levinson W.
      • et al.
      High utilizers of emergency health services in a population-based cohort of homeless adults.
      ]. Low ED use was defined as no more than 2 annual ED visits, moderate was defined as between 3 and 10 annual ED visits, and patients with more than 10 annual ED visits were considered to be the high ED users.

      2.3 Statistics

      Categorical data in comparison of groups were analyzed by using the Pearson χ2 test. Continuous data between 2 groups were analyzed using Student t test. Analysis of variance with Bonferroni correction was used to analyze differences between several groups. Kendall τ-b correlation coefficiency (τβ), which is reported better to determine the strength of relationships, was used to analyze the association among variables [
      • Raschke M.
      • Schlapfer M.
      • Nibali R.
      Measuring degree-degree association in networks.
      ]. Strength of relationships was determined as follows: (1) strong correlations were τβ > 0.5, (2) moderate correlations had values between 0.2 and 0.5, and (3) values less than 0.2 signified a weak relationship. All statistical analyses were performed using a 95% confidence interval with STATA 12.0 (College Station, TX) and a P < .05 was considered statistically significant.

      3. Results

      New York University ED Algorithm was deemed applicable to 54% (2886/5336) of all ED visits involving the study population. Appropriate vs inappropriate ED use was then determined among that group. Seventy-six percent (2188/2886) of these visits were considered inappropriate based on NYUA. Furthermore, patients with noncharity care insurance were excluded from this study yielding a total of 2396 ED visits by 867 homeless patients in the final analysis. Results showed that 76% (1828/2396) of ED visits were deemed to be inappropriate. No difference was found when compared with the group mentioned above (Fig. 1). In addition, the basic demographics between homeless ED visits included in this study vs those excluded were compared, and our results indicate that no significant population selection bias occurred between these 2 groups (see Appendix Table 1, Appendix Table 2)
      Figure thumbnail gr1
      Fig. 1Flow diagram of patients placed in final analysis.
      When further segregating homeless patients into 2 different groups based on insurance coverages, 77.14% of ED visits were considered inappropriate among patients with charity care coverage. There was no statistically significant difference when comparing charity care coverage patients with patients having no insurance coverage (74.05% inappropriate ED visits, P = .112, Table 1). More than 50% of ED arrivals via private vehicles in homeless patients were deemed to be associated with inappropriate use and more than 50% of ED arrivals via ambulance were deemed appropriate ED use. Patients with PCP assignments also had more inappropriate ED use than those without (Table 1). In addition, a higher frequency of inappropriate vs appropriate ED visits occurred per homeless patient (2.42 vs 1.90, P = .0145). Patients with inappropriate ED visits tended to be younger than those with appropriate ED visits (P < .05). No statistically significant difference was noted when factoring race, ethnicity, or weekend ED usage as contributors (Table 1).
      Table 1Comparisons of the appropriateness of ED use in homeless patients
      ED visits (total 2396 ED visits in 867 homeless patients)
      Inappropriate ED visits (n = 1828) (total 755 patients)Appropriate ED visits (n = 568) (total 298 patients)P
      Age (mean ± SD, 95% CI)44.54 ± 11.2346.02 ± 10.34.049
      Sex (male, %)431 (57.09%)191 (64.09%).037
      Race (%).412
       White or Caucasian318 (47.42%)143 (47.99%)
       Black or African American347 (45.96%)128 (42.95%)
       American Indian or Alaska Native3 (0.40%)1 (0.34%)
       Asian1 (0.13%)0 (0)
       Other43 (5.70%)26 (8.72%)
       Unknown3 (0.40%)0 (0)
      Ethnicity (%)
       Hispanic or Latino43 (5.70%)24 (8.05%).289
       Not Hispanic or Latino711 (94.17%)273 (91.61%)
       Unknown1 (0.13%)1 (0.34%)
      Mode of arrival (%)
       Ambulance584 (31.95%)292 (51.41%)<.0001
       Private car1,005 (54.98%)214 (37.68%)
       Public transportation147 (8.04%)27 (4.75%)
      Insurance type (%)
       Charity care coverage1340 (77.14%)397 (22.86%).112
       No insurance coverage488 (74.05%)171 (25.95%)
      Primary care physician (yes, %)904 (49.45%)249 (43.84%).019
      ED visits during the weekend (yes, %)447 (24.45%)156 (27.46%).149
      Average ED visits (mean ± SD, 95% CI)2.42 ± 3.10 (2.19-2.64)1.90 ± 3.00 (1.56-2.24).0145
      Analysis of the subset of homeless patients with inappropriate ED use through comparisons between those with charity care insurance and those with no insurance coverage showed that only 15.98% of the no insurance coverage group had PCP clinic assignments as compared with 61.64% of those with charity care coverage (P < .01). Potential confounders such as race, ethnicity, or weekend ED usage were explored in group comparisons. However, only age was found to be an independent risk factor in both the univariate and multivariate regression analyses (Table 2, Appendix Table 3). To determine the relationship between PCP assignment and patient insurance status, a Kendall τβ correlation coefficiency test was performed. These results showed that PCP assignment was moderately associated with patients receiving insurance coverage (τβ = 0.2898) indicating PCP assignment is another factor determining whether charity insurance could affect inappropriate ED use. Overall, the average number of inappropriate ED visits in patients with charity care coverage was greater than those without (2.73 vs 1.80, P < .01, Table 2).
      Table 2Comparison of inappropriate ED use in homeless patients with different insurance status
      Inappropriate ED visits in homeless patients (total ED visits = 1828)
      ED visits in patients with charity care (n = 1340) (498 patients)ED visits in patients with self pay (n = 488) (257 patients)P
      Age (y, mean ± SD)45.35 ± 11.2043.03 ± 11.16.007
      Sex (male, %, n)275 (55.22%)156 (60.70%).149
      Race (%, n)
      African American253 (50.80%)94 (36.58%).004
      Caucasian219 (43.98%)139 (54.09%)
      Ethnicity (%, n)
      Hispanic24 (4.82%)19 (7.39%).274
      Not Hispanic473 (94.98%)238 (92.61%)
      Mode of arrival (%)
      Ambulance (yes)433 (32.31%)151 (30.94%).578
      PCP (yes, %)826 (61.64%)78 (15.98%)<.001
      ED visits during the weekend (yes, %)332 (24.78%)115 (23.57%).594
      Average ED visits (mean ± SD)2.73 ± 3.531.80 ± 1.87.0001
      Further analysis focused on inappropriate ED use comparisons of homeless patients with different health care coverages, PCP assignments, and frequency of ED use. Frequency of ED use was divided into 3 groups (low, no more than 2 ED visits per year; moderate, between 3 and 10 ED visits per year; and high, more than 10 ED visits per year). When analyzing only homeless patients with inappropriate ED use, fewer high ED users were found among both the charity care and no insurance coverage groups (P < .001, Fig. 2). In addition, among more frequent ED users, homeless patients tended to have decreased numbers of inappropriate ED visits regardless of their PCP assignment status (P > .05, Fig. 3).
      Figure thumbnail gr2
      Fig. 2Association of inappropriate ED use in homeless patients with different numbers of ED visits.
      Figure thumbnail gr3
      Fig. 3Percentages of the inappropriate ED use with PCP assignments.

      4. Discussion

      The goal of this study was to pool all special charity insurance programs together including Medicaid and other national and regional charity care programs and compare that group with patients with no insurance coverage. Our results indicate that ED use patterns in these patients are not impacted whether a charity care program is provided regardless of the specific type of charity care program in place. In line with the available data [
      • McWilliams A.
      • Tapp H.
      • Barker J.
      • Dulin M.
      Cost analysis of the use of emergency departments for primary care services in Charlotte, North Carolina.
      ,
      • Aksoy H.
      • Aksoy U.
      • Ozturk M.
      • Ozyurt S.
      • Acmaz G.
      • Karadag O.I.
      • et al.
      Utilization of emergency service of obstetrics and gynecology: a cross-sectional analysis of a training hospital.
      ,
      • Han B.
      • Wells B.L.
      Inappropriate emergency department visits and use of the Health Care for the Homeless Program services by Homeless adults in the northeastern United States.
      ,
      • Dent A.W.
      • Phillips G.A.
      • Chenhall A.J.
      • McGregor L.R.
      The heaviest repeat users of an inner city emergency department are not general practice patients.
      ], we found that homeless patients use the ED inappropriately 76% of the time. These results suggest that providing charity care and assigning PCP clinics as 2 independent interventions do not prevent homeless patients from using the ED inappropriately. However, fewer inappropriate ED visits occur in patients with higher frequency ED use regardless of PCP assignment.
      Although use of the NYUA to determine appropriateness of ED use is well validated [
      • McWilliams A.
      • Tapp H.
      • Barker J.
      • Dulin M.
      Cost analysis of the use of emergency departments for primary care services in Charlotte, North Carolina.
      ,
      • Kaskie B.
      • Obrizan M.
      • Cook E.A.
      • Jones M.P.
      • Liu L.
      • Bentler S.
      • et al.
      Defining emergency department episodes by severity and intensity: A 15-year study of Medicare beneficiaries.
      ], it has been rarely applied to homeless patients who are a special needs population with higher rates of coexisting disorders, chronic physical disease, and mental illness. Our data suggest that it is a valuable tool in determining appropriate vs inappropriate ED use among homeless patients and aligns with the existing data in the literature. We found a higher frequency of inappropriate ED use by homeless men and a high ambulance transportation rate with frequent inappropriate ED visits among charity care–insured patients [
      • Coe A.B.
      • Moczygemba L.R.
      • Harpe S.E.
      • Gatewood S.B.
      Homeless patients' use of urban emergency departments in the United States.
      ,
      • Oates G.
      • Tadros A.
      • Davis S.M.
      A comparison of National Emergency Department use by homeless versus non-homeless people in the United States.
      ].
      In contrast to studies that only focus on Medicaid patients in relation to ED use [
      • Hookey S.J.
      StreetHealth - improving access to primary care.
      ,
      • Ku B.S.
      • Fields J.M.
      • Santana A.
      • Wasserman D.
      • Borman L.
      • Scott K.C.
      The Urban Homeless: Super-users of the Emergency Department.
      ,
      • Zur J.
      • Mojtabai R.
      • Li S.
      The cost savings of expanding Medicaid eligibility to include currently uninsured homeless adults with substance use disorders.
      ,
      • Tsai J.
      • Rosenheck R.A.
      • Culhane D.P.
      • Artiga S.
      Medicaid expansion: chronically homeless adults will need targeted enrollment and access to a broad range of services.
      ], the patient population served in our level I trauma hospital allowed us to investigate ED overuse as a function of the different kinds of charity care available to homeless patients. Tsai et al [
      • Tsai J.
      • Rosenheck R.A.
      • Culhane D.P.
      • Artiga S.
      Medicaid expansion: chronically homeless adults will need targeted enrollment and access to a broad range of services.
      ] found that most homeless patients are not enrolled in the Medicaid program and are therefore either left uninsured or become a tax burden of the state, county, or city to compensate for hospital costs. This finding aligns with our results and indicates the importance of investigating homeless patients with different types of charity care coverage [
      • Tsai J.
      • Rosenheck R.A.
      • Culhane D.P.
      • Artiga S.
      Medicaid expansion: chronically homeless adults will need targeted enrollment and access to a broad range of services.
      ].
      The challenges of favorably impacting homeless patients and their inappropriate use of ED resources are multifactorial. One of the potential barriers may be personal finances thereby virtually eliminating individual ability to appropriately access the health care system and leaving the ED as the only option [
      • Linton K.F.
      • Shafer M.S.
      Factors associated with the health service utilization of unsheltered, chronically homeless adults.
      ]. Some studies suggest that providing charity health insurance and assigning these patients to PCPs offer a potential solution thereby minimizing inappropriate ED use [
      • Chwastiak L.
      • Tsai J.
      • Rosenheck R.
      Impact of health insurance status and a diagnosis of serious mental illness on whether chronically homeless individuals engage in primary care.
      ,
      • Kreider B.
      • Nicholson S.
      Health insurance and the homeless.
      ]. However, our study showed that simply assigning homeless patients to PCP clinics did not prevent them from using the ED inappropriately (Fig. 3). Similar results have been reported in previous studies as well [
      • Kushel M.B.
      • Perry S.
      • Bangsberg D.
      • Clark R.
      • Moss A.R.
      Emergency department use among the homeless and marginally housed: results from a community-based study.
      ,
      • O'Toole T.P.
      • Buckel L.
      • Bourgault C.
      • Blumen J.
      • Redihan S.G.
      • Jiang L.
      • et al.
      Applying the chronic care model to homeless veterans: effect of a population approach to primary care on utilization and clinical outcomes.
      ]. Based on our experiences with this patient population, these results may be caused by a lack of hospital staff reinforcement, irregular and/or sporadic patient communication, and inappropriate referrals to the ED by emergency shelter case managers and executive directors who interpret all illnesses as a need to call “911.” Moreover, homeless persons who are only slightly ill may find more comfort in an ED waiting room than in a line waiting for a shelter bed. In these examples, proactive education across all community outreach organizations and hospital staff may be highly effective in reducing ED use. Taken together, simply providing PCP assignment does not seem to be effective if not combined with other supportive interventions such as housing and case management access [
      • Sadowski L.S.
      • Kee R.A.
      • VanderWeele T.J.
      • Buchanan D.
      Effect of a housing and case management program on emergency department visits and hospitalizations among chronically ill homeless adults: a randomized trial.
      ,
      • Gabrielian S.
      • Yuan A.H.
      • Andersen R.M.
      • Rubenstein L.V.
      • Gelberg L.
      VA health service utilization for homeless and low-income Veterans: a spotlight on the VA Supportive Housing (VASH) program in greater Los Angeles.
      ,
      • Tsai J.
      • Rosenheck R.A.
      Consumer choice over living environment, case management, and mental health treatment in supported housing and its relation to outcomes.
      ].
      Another possible intervention to minimize inappropriate ED use is to recognize the visitation patterns in these patients. Some studies showed the more ED visits per patient, the more inappropriate use by a given patient [
      • Han B.
      • Wells B.L.
      Inappropriate emergency department visits and use of the Health Care for the Homeless Program services by Homeless adults in the northeastern United States.
      ,
      • Olsson M.
      • Hansagi H.
      Repeated use of the emergency department: qualitative study of the patient's perspective.
      ]. Our study showed a different pattern with fewer inappropriate ED visits among higher frequency ED users (Fig. 2). This is in part because of early recognition of high users by case managers in this hospital. Once identified, these patients are enrolled in the community or emergency medicine service outreach program, which seems to help minimize inappropriate ED visits. Although text messaging and proactive case management designed to remind patients of clinical outpatient appointments may significantly increase overall clinic visits in some patient populations [
      • McInnes D.K.
      • Petrakis B.A.
      • Gifford A.L.
      • Rao S.R.
      • Houston T.K.
      • Asch S.M.
      • et al.
      Retaining homeless veterans in outpatient care: a pilot study of mobile phone text message appointment reminders.
      ,
      • Rice E.
      • Lee A.
      • Taitt S.
      Cell phone use among homeless youth: potential for new health interventions and research.
      ], it is still uncertain whether increased clinic visit frequency will decrease inappropriate ED use in the homeless. Whether increasing outpatient services will mitigate inappropriate ED use is unclear. Therefore, future multisite studies examining the efficacy of combined interventions designed to minimize inappropriate ED use in homeless patients are needed.

      5. Conclusions

      Overall, our study showed frequent inappropriate ED visits among homeless patients. Simply providing charity care and PCP assignments is insufficient to significantly redirect this cohort of patients to access the health care system in a more cost-effective manner. Recognizing ED visit patterns and committing to alternative resources and interventions should be considered as viable means to minimize inappropriate ED use among the homeless population.

      5.1 Limitation

      This was a retrospective study using homeless patient data from a single urban publicly funded hospital. The retrospective methodology limits its applicability including potential bias regarding the accuracy of information, potential selection bias because of 1 institutional database, lack of follow-up data, and missing data for analysis. With respect to the homeless population, patients were determined to have met criteria associated with a status of homeless at the time they registered at the ED. We are not able to determine the total length of homeless status of an individual patient. We are also unable to determine the association between the length of individual homeless status and associated ED use patterns. Using NYUA to determine ED use patterns might not be accurate based on a given selected population. Determination of ED use patterns is sophisticated, and none of the tools currently in use are considered reliable. This study also did not analyze the accuracy of combining NYUA with individual patient acuity levels to determine relative appropriateness of ED use among homeless patients. Furthermore, in this study, patients with uncertain use patterns (such as unclassified, split, or excluded by NYUA) were not included for data analysis. This may potentially result in bias because of incomplete patient population selection. The study hospital also has an emergency psychiatric unit that may further diverge the study population. Therefore, when analyzing and interpreting ED use, one must consider the potential impact of different patient populations and ED settings on study outcomes.
      Competing Interests: N/A
      Author contributions: H.W., V.A.N., and R.D.R. conceived the study and developed the design in consultation with all of the authors. D.Z., C.S., C.P., and J.K. assembled the data set and collected the data. H.W., V.A.N., R.D.R., and N.R.Z. conducted the statistical analyses and drafted the article, and all authors read and approved the final article. H.W. takes responsibility for the article as a whole.

      Appendix A.

      Appendix Table 1Comparisons of the ED use in homeless patients included in this study vs those excluded
      ED visits (total 5336 ED visits in 1454 homeless patients)
      ED visits included

      (n = 2886)
      ED visits excluded

      (n = 2450)
      P
      Age (mean ± SD, 95% CI)46.06 ± 11.1245.09 ± 11.19.0016
      Sex (male, %)1746 (60.50%)1525 (62.24%).192
      Race (%).001
       White or caucasian1314 (45.53%)1256 (51.27%)
       Black or African American1389 (48.13%)1053 (42.98%)
       American Indian or Alaska Native13 (0.45%)10 (0.41%)
       Asian1 (0.03%)4 (0.16%)
       Other165 (5.72%)125 (5.10%)
       Unknown4 (0.14%)2 (0.08%)
      Ethnicity (%).696
       Hispanic or Latino158 (5.47%)132 (5.39%)
       Not Hispanic or Latino2725 (94.42%)2317 (94.57%)
       Unknown3 (0.10%)1 (0.04%)
      Mode of arrival (%)
       Ambulance1079 (37.39%)868 (35.43%).048
       Private car1411 (48.89%)1136 (46.37%)
       Public transportation222 (7.69%)228 (9.31%)
      Insurance type (%)
       Charity care coverage1737 (60.19%)1463 (59.71%).078
       No insurance coverage659 (22.83%)613 (25.02%)
      Primary care physician (yes, %)1314 (45.53%)1041 (42.49%).026
      ED visits during the weekend (yes, %)721 (24.98%)655 (26.73%).145
      Appendix Table 2Adjusted odds ratios of variables to affect the patient population selection in this study
      VariablesAdjusted odds ratio95% confidence intervalP
      Age1.001.00-1.01.006
      African American1.000.79-1.26.996
      White or Caucasian0.800.63-1.01.070
      Primary care physician assignment1.070.96-1.20.186
      Appendix Table 3Adjusted odds ratios of variables to affect the inappropriate ED use between homeless patients with charity vs no insurance coverages
      VariablesAdjusted odds ratio95% confidence intervalP
      Age0.970.96-0.98<.001
      African American0.830.45-1.52.553
      White or Caucasian1.050.57-1.94.856
      Primary care physician assignment3.222.51-4.14<.001

      References

        • Hoshide R.R.
        • Manog J.D.
        • Noh T.
        • Omori J.
        Barriers to healthcare of homeless residents of three Honolulu shelters.
        Hawaii Med J. 2011; 70: 214-216
        • Tankimovich M.
        Barriers to and interventions for improved tuberculosis detection and treatment among homeless and immigrant populations: a literature review.
        J Community Health Nurs. 2013; 30: 83-95
        • Hwang S.W.
        • Chambers C.
        • Chiu S.
        • Katic M.
        • Kiss A.
        • Redelmeier D.A.
        • et al.
        A comprehensive assessment of health care utilization among homeless adults under a system of universal health insurance.
        Am J Public Health. 2013; 103: S294-S301
        • Levy B.D.
        • O'Connell J.J.
        Health care for homeless persons.
        N Engl J Med. 2004; 350: 2329-2332
        • Tsai J.
        • Doran K.M.
        • Rosenheck R.A.
        When health insurance is not a factor: national comparison of homeless and nonhomeless US veterans who use Veterans Affairs Emergency Departments.
        Am J Public Health. 2013; 103: S225-S231
        • Coe A.B.
        • Moczygemba L.R.
        • Harpe S.E.
        • Gatewood S.B.
        Homeless patients' use of urban emergency departments in the United States.
        J Ambul Care Manage. 2015; 38: 48-58
        • de Araujo P.
        • Khraiche M.
        • Tukan A.
        Does overcrowding and health insurance type impact patient outcomes in emergency departments?.
        Health Econ Rev. 2013; 3: 25
        • Hoot N.R.
        • Aronsky D.
        Systematic review of emergency department crowding: causes, effects, and solutions.
        Ann Emerg Med. 2008; 52: 126-136
        • Gandhi S.O.
        • Grant L.P.
        • Sabik L.M.
        Trends in nonemergent use of emergency departments by health insurance status.
        Med Care Res Rev. 2014; 71: 496-521
        • Ballard D.W.
        • Price M.
        • Fung V.
        • Brand R.
        • Reed M.E.
        • Fireman B.
        • et al.
        Validation of an algorithm for categorizing the severity of hospital emergency department visits.
        Med Care. 2010; 48: 58-63
        • Begley C.E.
        • Vojvodic R.W.
        • Seo M.
        • Burau K.
        Emergency room use and access to primary care: evidence from Houston, Texas.
        J Health Care Poor Underserved. 2006; 17: 610-624
        • Capp R.
        • Rosenthal M.S.
        • Desai M.M.
        • Kelley L.
        • Borgstrom C.
        • Cobbs-Lomax D.L.
        • et al.
        Characteristics of Medicaid enrollees with frequent ED use.
        Am J Emerg Med. 2013; 31: 1333-1337
        • Chwastiak L.
        • Tsai J.
        • Rosenheck R.
        Impact of health insurance status and a diagnosis of serious mental illness on whether chronically homeless individuals engage in primary care.
        Am J Public Health. 2012; 102: e83-e89
        • Bharel M.
        • Lin W.C.
        • Zhang J.
        • O'Connell E.
        • Taube R.
        • Clark R.E.
        Health care utilization patterns of homeless individuals in Boston: preparing for Medicaid expansion under the Affordable Care Act.
        Am J Public Health. 2013; 103: S311-S317
        • Hookey S.J.
        StreetHealth - improving access to primary care.
        Aust Fam Physician. 2012; 41: 67-69
        • Weber M.
        • Thompson L.
        • Schmiege S.J.
        • Peifer K.
        • Farrell E.
        Perception of access to health care by homeless individuals seeking services at a day shelter.
        Arch Psychiatr Nurs. 2013; 27: 179-184
        • Schoon P.M.
        • Champlin B.E.
        • Hunt R.J.
        Developing a sustainable foot care clinic in a homeless shelter within an academic-community partnership.
        J Nurs Educ. 2012; 51: 714-718
        • Maizels M.
        Health resource utilization of the emergency department headache "repeater".
        Headache. 2002; 42: 747-753
        • Chambers C.
        • Chiu S.
        • Katic M.
        • Kiss A.
        • Redelmeier D.A.
        • Levinson W.
        • et al.
        High utilizers of emergency health services in a population-based cohort of homeless adults.
        Am J Public Health. 2013; 103: S302-S310
        • Raschke M.
        • Schlapfer M.
        • Nibali R.
        Measuring degree-degree association in networks.
        Phys Rev E Stat Nonlin Soft Matter Phys. 2010; 82: 037102
        • McWilliams A.
        • Tapp H.
        • Barker J.
        • Dulin M.
        Cost analysis of the use of emergency departments for primary care services in Charlotte, North Carolina.
        N C Med J. 2011; 72: 265-271
        • Aksoy H.
        • Aksoy U.
        • Ozturk M.
        • Ozyurt S.
        • Acmaz G.
        • Karadag O.I.
        • et al.
        Utilization of emergency service of obstetrics and gynecology: a cross-sectional analysis of a training hospital.
        J Clin Med Res. 2015; 7: 109-114
        • Han B.
        • Wells B.L.
        Inappropriate emergency department visits and use of the Health Care for the Homeless Program services by Homeless adults in the northeastern United States.
        J Public Health Manag Pract. 2003; 9: 530-537
        • Dent A.W.
        • Phillips G.A.
        • Chenhall A.J.
        • McGregor L.R.
        The heaviest repeat users of an inner city emergency department are not general practice patients.
        Emerg Med (Fremantle). 2003; 15: 322-329
        • Kaskie B.
        • Obrizan M.
        • Cook E.A.
        • Jones M.P.
        • Liu L.
        • Bentler S.
        • et al.
        Defining emergency department episodes by severity and intensity: A 15-year study of Medicare beneficiaries.
        BMC Health Serv Res. 2010; 10: 173
        • Oates G.
        • Tadros A.
        • Davis S.M.
        A comparison of National Emergency Department use by homeless versus non-homeless people in the United States.
        J Health Care Poor Underserved. 2009; 20: 840-845
        • Ku B.S.
        • Fields J.M.
        • Santana A.
        • Wasserman D.
        • Borman L.
        • Scott K.C.
        The Urban Homeless: Super-users of the Emergency Department.
        Popul Health Manag. 2014; 17: 366-371
        • Zur J.
        • Mojtabai R.
        • Li S.
        The cost savings of expanding Medicaid eligibility to include currently uninsured homeless adults with substance use disorders.
        J Behav Health Serv Res. 2014; 41: 110-124
        • Tsai J.
        • Rosenheck R.A.
        • Culhane D.P.
        • Artiga S.
        Medicaid expansion: chronically homeless adults will need targeted enrollment and access to a broad range of services.
        Health Aff (Millwood). 2013; 32: 1552-1559
        • Linton K.F.
        • Shafer M.S.
        Factors associated with the health service utilization of unsheltered, chronically homeless adults.
        Soc Work Public Health. 2014; 29: 73-80
        • Kreider B.
        • Nicholson S.
        Health insurance and the homeless.
        Health Econ. 1997; 6: 31-41
        • Kushel M.B.
        • Perry S.
        • Bangsberg D.
        • Clark R.
        • Moss A.R.
        Emergency department use among the homeless and marginally housed: results from a community-based study.
        Am J Public Health. 2002; 92: 778-784
        • O'Toole T.P.
        • Buckel L.
        • Bourgault C.
        • Blumen J.
        • Redihan S.G.
        • Jiang L.
        • et al.
        Applying the chronic care model to homeless veterans: effect of a population approach to primary care on utilization and clinical outcomes.
        Am J Public Health. 2010; 100: 2493-2499
        • Sadowski L.S.
        • Kee R.A.
        • VanderWeele T.J.
        • Buchanan D.
        Effect of a housing and case management program on emergency department visits and hospitalizations among chronically ill homeless adults: a randomized trial.
        JAMA. 2009; 301: 1771-1778
        • Gabrielian S.
        • Yuan A.H.
        • Andersen R.M.
        • Rubenstein L.V.
        • Gelberg L.
        VA health service utilization for homeless and low-income Veterans: a spotlight on the VA Supportive Housing (VASH) program in greater Los Angeles.
        Med Care. 2014; 52: 454-461
        • Tsai J.
        • Rosenheck R.A.
        Consumer choice over living environment, case management, and mental health treatment in supported housing and its relation to outcomes.
        J Health Care Poor Underserved. 2012; 23: 1671-1677
        • Olsson M.
        • Hansagi H.
        Repeated use of the emergency department: qualitative study of the patient's perspective.
        Emerg Med J. 2001; 18: 430-434
        • McInnes D.K.
        • Petrakis B.A.
        • Gifford A.L.
        • Rao S.R.
        • Houston T.K.
        • Asch S.M.
        • et al.
        Retaining homeless veterans in outpatient care: a pilot study of mobile phone text message appointment reminders.
        Am J Public Health. 2014; 104: S588-S594
        • Rice E.
        • Lee A.
        • Taitt S.
        Cell phone use among homeless youth: potential for new health interventions and research.
        J Urban Health. 2011; 88: 1175-1182