Louise Durand1, Fiona Boland2, Denis O'Driscoll3, Kathleen Bennett4, Joseph Barry5, Eamon Keenan6, Tom Fahey7, Gráinne Cousins8. 1. School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland, St. Stephen's Green, Dublin 2, Ireland. 2. HRB Centre for Primary Care Research, Royal College of Surgeons in Ireland, Lower Mercer Street, Dublin 2, Ireland; Data Science Centre, Royal College of Surgeons in Ireland, Lower Mercer Street, Dublin 2, Ireland. 3. Addiction Services, Health Service Executive, Dublin, Ireland. 4. Data Science Centre, Royal College of Surgeons in Ireland, Lower Mercer Street, Dublin 2, Ireland; Division of Population Health Sciences, Royal College of Surgeons in Ireland, Lower Mercer Street, Dublin 2, Ireland. 5. Department of Public Health and Primary Care, Trinity College Dublin, Dublin 2, Ireland. 6. National Social Inclusion Office, Health Service Executive, Stewarts Hospital, Dublin 20, Ireland. 7. HRB Centre for Primary Care Research, Royal College of Surgeons in Ireland, Lower Mercer Street, Dublin 2, Ireland. 8. School of Pharmacy and Biomolecular Sciences, Royal College of Surgeons in Ireland, St. Stephen's Green, Dublin 2, Ireland. Electronic address: gcousins@rcsi.ie.
Abstract
BACKGROUND: Retention in methadone maintenance treatment (MMT) is associated with reduced illicit drug use, criminal activity, and mortality; however, many clients move in and out of MMT. This study aims to identify determinants of time to dropout of MMT across multiple treatment episodes in specialist addiction services in Ireland. METHODS: Cohort study of persons attending specialist addiction clinics between 2010 and 2015. MMT episodes were periods of continuous treatment if there were no interruptions to treatment lasting > 7days. Proportional hazards frailty models were used to assess factors associated with time to dropout from recurrent MMT episodes at 3 (90 days) and 12 months (91-365 days). MMT episodes were right- censored at time of death, transfer to prison or primary care, and study end. RESULTS: A total of 2,035 individuals experienced 4,969 MMT episodes, with 2,724 dropout events during the six-year follow-up. Factors associated with dropout at 3 months included low dose methadone (<60 mg/day) (HR = 1.49, 95% CI 1.29-1.73) and previous dropout (HR = 1.65, 95% CI 1.41-1.92). Adherence was protective (HR = 0.91, 95% CI 0.90-0.92). Dropout at 12 months was associated with low dose methadone (HR = 1.44, 95% CI 1.23-1.68), previous dropout (HR = 1.37, 95% CI 1.16-1.61), males (HR 1.26, 95% CI 1.06-1.50), benzodiazepines (HR = 1.22, 95% CI 1.03-1.45) and number of comorbidities (HR = 1.12, 95% CI 1.05-1.20); adherence was protective (HR = 0.86, 95% CI 0.84-0.87). CONCLUSIONS: Clients with a previous history of treatment dropout and those on low dose methadone should be identified as high risk for both early and later dropout. Inversely, adherence to treatment, not missing methadone doses, is protective.
BACKGROUND: Retention in methadone maintenance treatment (MMT) is associated with reduced illicit drug use, criminal activity, and mortality; however, many clients move in and out of MMT. This study aims to identify determinants of time to dropout of MMT across multiple treatment episodes in specialist addiction services in Ireland. METHODS: Cohort study of persons attending specialist addiction clinics between 2010 and 2015. MMT episodes were periods of continuous treatment if there were no interruptions to treatment lasting > 7days. Proportional hazards frailty models were used to assess factors associated with time to dropout from recurrent MMT episodes at 3 (90 days) and 12 months (91-365 days). MMT episodes were right- censored at time of death, transfer to prison or primary care, and study end. RESULTS: A total of 2,035 individuals experienced 4,969 MMT episodes, with 2,724 dropout events during the six-year follow-up. Factors associated with dropout at 3 months included low dose methadone (<60 mg/day) (HR = 1.49, 95% CI 1.29-1.73) and previous dropout (HR = 1.65, 95% CI 1.41-1.92). Adherence was protective (HR = 0.91, 95% CI 0.90-0.92). Dropout at 12 months was associated with low dose methadone (HR = 1.44, 95% CI 1.23-1.68), previous dropout (HR = 1.37, 95% CI 1.16-1.61), males (HR 1.26, 95% CI 1.06-1.50), benzodiazepines (HR = 1.22, 95% CI 1.03-1.45) and number of comorbidities (HR = 1.12, 95% CI 1.05-1.20); adherence was protective (HR = 0.86, 95% CI 0.84-0.87). CONCLUSIONS: Clients with a previous history of treatment dropout and those on low dose methadone should be identified as high risk for both early and later dropout. Inversely, adherence to treatment, not missing methadone doses, is protective.
Authors: Antoine Chaillon; Chrianna Bharat; Jack Stone; Nicola Jones; Louisa Degenhardt; Sarah Larney; Michael Farrell; Peter Vickerman; Matthew Hickman; Natasha K Martin; Annick Bórquez Journal: Addiction Date: 2021-12-04 Impact factor: 7.256