title: A Multi-State Model Examining Patterns of Transitioning Among States of Engagement in Care in HIV-Positive Individuals Initiating Combination Antiretroviral Therapy.
abstract: BACKGROUND
  Common measures of engagement in care fail to acknowledge that infrequent follow-up may occur either intentionally among patients with sustained virologic suppression or unintentionally among patients with poor clinical outcomes.
  
  
  METHODS
  Five states of HIV care were defined within the Canadian Observational Cohort Collaboration following combination antiretroviral therapy (cART) initiation: (1) guidelines HIV care [suppressed viral load (VL) and CD4 >200 cells per cubic millimeter, no gaps in cART >3 months, no gaps in CD4 or VL measurement >6 months], (2) successful care with decreased frequency of follow-up (as above except no gaps in CD4 or VL measurement >12 months), (3) suboptimal care (unsuppressed VL, CD4 <200 cells per cubic millimeter on 2 consecutive visits, ≥1 gap in cART >3 months, or ≥1 gap in CD4 or VL measurement >12 months), (4) loss to follow-up (no contact for 18 months), and (5) death. Multi-state models were used to determine factors associated with transitioning among states.
  
  
  RESULTS
  In total, 7810 participants were included. Younger age, female gender, Indigenous ethnicity, and people who have injected drugs were associated with increased likelihoods of transitioning from guidelines to suboptimal care and decreased likelihoods of transitioning from suboptimal to guidelines care. One-fifth of individuals in successful, decreased follow-up after cART initiation (mean sojourn time 0.72 years) were in suboptimal care in subsequent years.
  
  
  CONCLUSIONS
  Using routinely collected data, we have developed a flexible framework that characterizes patient transitions among states of HIV clinical care. We have demonstrated that multi-state models provide a useful approach to supplement "cascade of care" work.
authors.affiliation: *Toronto General Research Institute, University Health Network, Toronto, Ontario, Canada;†Dalla Lana School of Public Health, University of Toronto, Toronto, Ontario, Canada;‡Department of Medicine, University of Toronto, Toronto, Ontario, Canada;§Women's College Research Institute, Women's College Hospital, Toronto, Ontario, Canada;‖Maple Leaf Medical Clinic, Toronto, Ontario, Canada;¶Institute of Health Policy, Management and Evaluation, University of Toronto, Toronto, Ontario, Canada;#Centre for Urban Health Solutions, Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada;**Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada;††Department of Family and Community Medicine, St. Michael's Hospital, Toronto, Ontario, Canada;‡‡Department of Family and Community Medicine, University of Toronto, Toronto, Ontario, Canada;§§Immunodeficiency Clinic, Toronto General Hospital, University Health Network, Toronto, Ontario, Canada;‖‖The Ottawa Hospital Research Institute, University of Ottawa, Ottawa, Ontario, Canada;¶¶McGill University Health Centre, McGill University, Montreal, Québec, Canada;##Department of Medicine, McGill University, Montreal, Québec, Canada;***Clinique Médicale l'Actuel, Montreal, Québec, Canada;†††British Columbia Centre for Excellence in HIV/AIDS, Vancouver, British Columbia, Canada;‡‡‡Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada;§§§Department of Psychiatry, University of Toronto, Toronto, Ontario, Canada;‖‖‖Ontario HIV Treatment Network, Toronto, Ontario, Canada; and¶¶¶Faculty of Health Sciences, Simon Fraser University, Burnaby, British Columbia, Canada.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Gillis
authors.forename: Mona
authors.initials: M
authors.lastname: Loutfy
authors.forename: Ahmed M
authors.initials: AM
authors.lastname: Bayoumi
authors.forename: Tony
authors.initials: T
authors.lastname: Antoniou
authors.forename: Ann N
authors.initials: AN
authors.lastname: Burchell
authors.forename: Sharon
authors.initials: S
authors.lastname: Walmsley
authors.forename: Curtis
authors.initials: C
authors.lastname: Cooper
authors.forename: Marina B
authors.initials: MB
authors.lastname: Klein
authors.forename: Nima
authors.initials: N
authors.lastname: Machouf
authors.forename: Julio S G
authors.initials: JS
authors.lastname: Montaner
authors.forename: Sean B
authors.initials: SB
authors.lastname: Rourke
authors.forename: Christos
authors.initials: C
authors.lastname: Tsoukas
authors.forename: Robert
authors.initials: R
authors.lastname: Hogg
authors.forename: Janet
authors.initials: J
authors.lastname: Raboud
mesh_terms: D000328:Adult; D044966:Anti-Retroviral Agents / Q000627:therapeutic use*; D023241:Antiretroviral Therapy, Highly Active / Q000379:methods*; D018791:CD4 Lymphocyte Count; D002170:Canada; D015331:Cohort Studies; D005260:Female; D015658:HIV Infections / Q000175:diagnosis* / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology; D006801:Humans; D008297:Male; D055118:Medication Adherence; D008875:Middle Aged; D016896:Treatment Outcome; D019562:Viral Load
chemical_list: D044966:Anti-Retroviral Agents