title: A 10-year retrospective analysis of hospital admissions and length of stay among a cohort of homeless adults in Vancouver, Canada.
abstract: BACKGROUND
  Homelessness is associated with a very high prevalence of substance use and mental disorders and elevated levels of acute health service use. Among the homeless, little is known regarding the relative impact of specific mental disorders on healthcare utilization. The aim of the present study was to examine the association between different categories of diagnosed mental disorders with hospital admission and length of stay (LOS) in a cohort of homeless adults in Vancouver, Canada.
  
  
  METHODS
  Participants were recruited as part of an experimental trial in which participants met criteria for both homelessness and mental illness. Administrative data were obtained (with separate consent) including comprehensive records of acute hospitalizations during the 10 years prior to recruitment and while participants where experiencing homelessness. Generalized Estimating Equations were used to estimate the associations between outcome variables (acute hospital admissions and LOS) and predictor variables (specific disorders).
  
  
  RESULTS
  Among the eligible sample (n = 433) 80 % were hospitalized, with an average of 6.0 hospital admissions and 71.4 days per person during the 10-year observation period. Of a combined total 2601 admissions to hospital, 1982 were psychiatric and 619 were non-psychiatric. Significant (p <0.001) independent predictors of hospital admission and LOS included a diagnosis of schizophrenia or bipolar disorder, as well as high (≥32 service contacts) non-psychiatric medical service use in the community.
  
  
  CONCLUSIONS
  Our results demonstrate that specific mental disorders alongside high non-psychiatric service use were significantly associated with hospital admission and LOS. These findings suggest the importance of screening within the homeless population to identify individuals who may be at risk for acute illness and the implementation of services to promote recovery and prevent repeated hospitalization.
  
  
  BACKGROUND
  ISRCTN57595077 ; ISRCTN66721740.
authors.affiliation: Faculty of Health Sciences, Simon Fraser University, Simon Fraser University 8888 University Drive, Burnaby, BC, V5A 1S6, Canada. arussoli@sfu.ca.
authors.forename: Angela
authors.initials: A
authors.lastname: Russolillo
authors.affiliation: Faculty of Health Sciences, Simon Fraser University, Simon Fraser University 8888 University Drive, Burnaby, BC, V5A 1S6, Canada. akm_moniruzzaman@sfu.ca.
authors.forename: Akm
authors.initials: A
authors.lastname: Moniruzzaman
authors.affiliation: Faculty of Health Sciences, Simon Fraser University, Simon Fraser University 8888 University Drive, Burnaby, BC, V5A 1S6, Canada. spa16@sfu.ca.
authors.forename: Milad
authors.initials: M
authors.lastname: Parpouchi
authors.affiliation: Faculty of Health Sciences, Simon Fraser University, Simon Fraser University 8888 University Drive, Burnaby, BC, V5A 1S6, Canada. clauren@sfu.ca.
authors.forename: Lauren B
authors.initials: LB
authors.lastname: Currie
authors.affiliation: Faculty of Health Sciences, Simon Fraser University, Simon Fraser University 8888 University Drive, Burnaby, BC, V5A 1S6, Canada. jsomers@sfu.ca.
authors.forename: Julian M
authors.initials: JM
authors.lastname: Somers
mesh_terms: D000208:Acute Disease; D000328:Adult; D001955:British Columbia / Q000453:epidemiology; D005260:Female; D006703:Ill-Housed Persons / Q000523:psychology / Q000706:statistics & numerical data*; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D007902:Length of Stay / Q000706:statistics & numerical data; D008297:Male; D001523:Mental Disorders / Q000453:epidemiology / Q000628:therapy*; D015995:Prevalence; D012008:Recurrence; D012111:Residence Characteristics; D012189:Retrospective Studies; D019966:Substance-Related Disorders / Q000453:epidemiology