title: Barriers to Prescription Medication Adherence Among Homeless and Vulnerably Housed Adults in Three Canadian Cities.
abstract: OBJECTIVE
  Medication adherence is an important determinant of successful medical treatment. Marginalized populations, such as homeless and vulnerably housed individuals, may face substantial barriers to medication adherence. This study aimed to determine the prevalence of, reasons for, and factors associated with medication nonadherence among homeless and vulnerably housed individuals. Additionally, we examined the association between medication nonadherence and subsequent emergency department utilization during a 1-year follow-up period.
  
  
  METHODS
  Data were collected as part of the Health and Housing in Transition study, a prospective cohort study tracking the health and housing status of 595 homeless and 596 vulnerably housed individuals in 3 Canadian cities. Logistic regression was used to identify factors associated with medication nonadherence, as well as the association between medication nonadherence at baseline and subsequent emergency department utilization.
  
  
  RESULTS
  Among 716 participants who had been prescribed a medication, 189 (26%) reported nonadherence. Being ≥40 years old was associated with decreased likelihood of nonadherence (adjusted odds ratio [AOR] = 0.59; 95% confidence interval [CI] = 0.41-0.84), as was having a primary care provider (AOR = 0.49; 95% CI = 0.34-0.71). Having a positive screen on the AUDIT (Alcohol Use Disorders Identification Test; an indication of harmful or hazardous drinking) was associated with increased likelihood of nonadherence (AOR = 1.86; 95% CI = 1.31-2.63). Common reasons for nonadherence included side effects, cost, and lack of access to a physician. Self-reported nonadherence at baseline was significantly associated with frequent emergency department use (≥3 visits) over the follow-up period at the bivariate level (OR = 1.55; 95% CI = 1.02-2.35) but was not significant in a multivariate model (AOR = 1.49; 95% CI = 0.96-2.32).
  
  
  CONCLUSIONS
  Homeless and vulnerably housed individuals face significant barriers to medication adherence. Health care providers serving this population should be particularly attentive to nonadherence among younger patients and those with harmful or hazardous drinking patterns.
authors.affiliation: Centre for Research on Inner City Health, Keenan Research Centre in the Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada chunter2015@meds.uwo.ca.
authors.forename: Charlotte E
authors.initials: CE
authors.lastname: Hunter
authors.affiliation: Centre for Health Evaluation and Outcome Sciences, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Anita
authors.initials: A
authors.lastname: Palepu
authors.affiliation: University of Ottawa, Institute of Mental Health Research, Ottawa, Ontario, Canada.
authors.forename: Susan
authors.initials: S
authors.lastname: Farrell
authors.affiliation: Centre for Research on Inner City Health, Keenan Research Centre in the Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada.
authors.forename: Evie
authors.initials: E
authors.lastname: Gogosis
authors.affiliation: Centre for Research on Inner City Health, Keenan Research Centre in the Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada.
authors.forename: Kristen
authors.initials: K
authors.lastname: O'Brien
authors.affiliation: Centre for Research on Inner City Health, Keenan Research Centre in the Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada Division of General Internal Medicine, Department of Medicine, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Stephen W
authors.initials: SW
authors.lastname: Hwang
mesh_terms: D000328:Adult; D000367:Age Factors; D000428:Alcohol Drinking / Q000453:epidemiology*; D002170:Canada / Q000453:epidemiology; D005260:Female; D006703:Ill-Housed Persons / Q000706:statistics & numerical data*; D006801:Humans; D016015:Logistic Models; D008297:Male; D055553:Prescription Drugs / Q000008:administration & dosage*; D011446:Prospective Studies; D012307:Risk Factors; D057566:Self Report; D035862:Vulnerable Populations / Q000706:statistics & numerical data*; D016903:Drug Monitoring
chemical_list: D055553:Prescription Drugs
keywords: homelessness; medication adherence; urban health; vulnerable populations