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. 2020 Jul 23;17(1):51.
doi: 10.1186/s12954-020-00396-x.

A cohort study evaluating the association between concurrent mental disorders, mortality, morbidity, and continuous treatment retention for patients in opioid agonist treatment (OAT) across Ontario, Canada, using administrative health data

Kristen A Morin  1 , Joseph K Eibl  2 , Graham Gauthier  1 , Brian Rush  3 , Christopher Mushquash  1   4 , Nancy E Lightfoot  5 , David C Marsh  6   7   8   9
Affiliations

A cohort study evaluating the association between concurrent mental disorders, mortality, morbidity, and continuous treatment retention for patients in opioid agonist treatment (OAT) across Ontario, Canada, using administrative health data

Kristen A Morin et al. Harm Reduct J. .

Abstract

Background: Due to the high prevalence of mental disorders among people with opioid use disorder, the objective of this study was to determine the association between concurrent mental disorders, mortality, morbidity, and continuous treatment retention for patients in opioid agonist treatment in Ontario, Canada.

Methods: We conducted a retrospective cohort study of patients enrolled in opioid agonist treatment between January 1, 2011, and December 31, 2015. Patients were stratified into two groups: those diagnosed with concurrent mental disorders and opioid use disorder and those with opioid use disorder only, using data from the Ontario Health Insurance Plan Database, Ontario Drug Benefit Plan Database. The primary outcome studied was all-cause mortality using data from the Registered Persons Database. Emergency department visits from the National Ambulatory Care Database, hospitalizations Discharge Abstract Database, and continuous retention in treatment, defined as 1 year of uninterrupted opioid agonist treatment using data from the Ontario Drug Benefit Plan Database were measured as secondary outcomes. Encrypted patient identifiers were used to link information across databases.

Results: We identified 55,924 individuals enrolled in opioid agonist treatment, and 87% had a concurrent mental disorder diagnosis during this period. We observed that having a mental disorder was associated with an increased likelihood of all-cause mortality (odds ratio (OR) 1.4; 95% confidence interval (CI) 1.2-1.5). For patients diagnosed with mental disorders, the estimated rate of ED visits per year was 2.25 times higher and estimated rate of hospitalization per year was 1.67 times higher than for patients with no mental disorders. However, there was no association between having a diagnosis of a mental disorder and 1-year treatment retention in OAT-adjusted hazard ratio (HR) = 1.0; 95% CI 0.9 to 1.1.

Conclusion: Our findings highlight the consequences of the high prevalence of mental disorders for individuals with opioid use disorder in Ontario, Canada.

Keywords: Mental disorders; Opioid agonist treatment; Opioid use disorder.

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Conflict of interest statement

Dr. David Marsh maintains the following roles: Chief Medical Director at CATC (Canadian Addiction Treatment Center), opioid agonist therapy provider. Dr. Marsh has no ownership stake in the CATC as a stipendiary employee. We do not foresee any conflict of interest as data will be made freely available to the public, and neither the CATC nor the Universities prevent publication and dissemination of knowledge. The authors have no conflicts declared. This does not alter our adherence to the Harm Reduction Journal’s policies on sharing data and materials

Figures

Fig. 1
Fig. 1
Flow chart outlining data build including linkages. OAT, opioid agonist treatment; OHIP, Ontario Health Insurance Plan Database; RPDB, Registered Persons Database; NACRS, National Ambulatory Care Database; DAD, Discharge Abstract Database
Fig. 2
Fig. 2
Proportion of diagnoses of mental disorders for patients enrolled in OAT
Fig. 3
Fig. 3
Hazzard ratio time to discontinuation for patients undergoing methadone maintenance and buprenorphine/naloxone maintenance treatment
Fig. 4
Fig. 4
Proportion of patients for outcomes by place of residence. NR, northern rural; NU, northern urban; SR, southern rural; SU, southern urban
See this image and copyright information in PMC

References

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