Solmaz Amiri1, Katherine Hirchak2, Robert Lutz3, Michael G McDonell4, Sterling M McPherson4, John M Roll2, Ofer Amram5. 1. Department of Nutrition and Exercise Physiology, Elson S. Floyd College of Medicine, Washington State University, P.O. Box 1495, HERB 451, Spokane, 0WA 99210, USA. Electronic address: solmaz.amiri@wsu.edu. 2. Program of Excellence in Addiction Research, Washington State University, 412 E Spokane Falls Blvd, Spokane, WA, 99202, USA. 3. Department of Nutrition and Exercise Physiology, Elson S. Floyd College of Medicine, Washington State University, P.O. Box 1495, HERB 451, Spokane, 0WA 99210, USA; Spokane Regional Health District, 1101 W College Ave, Spokane, WA, 99201, USA. 4. Program of Excellence in Addiction Research, Washington State University, 412 E Spokane Falls Blvd, Spokane, WA, 99202, USA; Department of Medical Education and Clinical Sciences, Elson S Floyd College of Medicine, Washington State University, 412 E Spokane Falls Blvd, Spokane, WA, 99202, USA. 5. Department of Nutrition and Exercise Physiology, Elson S. Floyd College of Medicine, Washington State University, P.O. Box 1495, HERB 451, Spokane, 0WA 99210, USA.
Abstract
OBJECTIVE: To determine the effect of clinical, socio-demographic, and contextual characteristics on treatment retention in an opioid treatment program (OTP). METHODS: A retrospective longitudinal review of 851 clients who received methadone at the only state-funded OTP in Spokane County, Washington between 2015 and 2017. A time variable (the number of days in treatment) and a status indicator (to distinguish between clients who dropped out or censored) worked together to define retention in treatment. Our hypothesized covariates included: area deprivation, distance to the OTP, availability of cannabis retail outlets, availability of on-premise and off-premise alcohol outlets, methadone dosage, age, gender, race, and years on treatment. Cox regression within the family of survival analysis was used to model time-to-event data in the presence of censored cases. RESULTS: The median duration of retention was 394 (95%CI = 324-464) days. In the multivariable Cox regression, factors predicting treatment retention were area deprivation (HR = 1.79, 95%CI = 1.02-3.15, p = 0.04), age (HR=0.99, 95%CI=0.98-.99, p = 0.008), dosage of methadone (HR=0.98, 95%CI=0.98-0.98, p < 0.001), and the number of years on treatment (HR=1.12, 95%CI=1.06-1.18, p < 0.001). CONCLUSIONS: The findings of this study showed age and methadone dosage were protective factors and area deprivation and years on treatment were risk factors for treatment retention. After dichotomizing methadone dosage, a unique finding of this study was that higher dosage of methadone did not lead to increasingly smaller HRs for dropping out of treatment. Considering that opioid use disorder is a chronic condition, efforts need to be made to target factors associated with retention.
OBJECTIVE: To determine the effect of clinical, socio-demographic, and contextual characteristics on treatment retention in an opioid treatment program (OTP). METHODS: A retrospective longitudinal review of 851 clients who received methadone at the only state-funded OTP in Spokane County, Washington between 2015 and 2017. A time variable (the number of days in treatment) and a status indicator (to distinguish between clients who dropped out or censored) worked together to define retention in treatment. Our hypothesized covariates included: area deprivation, distance to the OTP, availability of cannabis retail outlets, availability of on-premise and off-premise alcohol outlets, methadone dosage, age, gender, race, and years on treatment. Cox regression within the family of survival analysis was used to model time-to-event data in the presence of censored cases. RESULTS: The median duration of retention was 394 (95%CI = 324-464) days. In the multivariable Cox regression, factors predicting treatment retention were area deprivation (HR = 1.79, 95%CI = 1.02-3.15, p = 0.04), age (HR=0.99, 95%CI=0.98-.99, p = 0.008), dosage of methadone (HR=0.98, 95%CI=0.98-0.98, p < 0.001), and the number of years on treatment (HR=1.12, 95%CI=1.06-1.18, p < 0.001). CONCLUSIONS: The findings of this study showed age and methadone dosage were protective factors and area deprivation and years on treatment were risk factors for treatment retention. After dichotomizing methadone dosage, a unique finding of this study was that higher dosage of methadone did not lead to increasingly smaller HRs for dropping out of treatment. Considering that opioid use disorder is a chronic condition, efforts need to be made to target factors associated with retention.
Authors: Martin Busch; Charlotte Klein; Alfred Uhl; Hans Haltmayer; Maurice Cabanis; Jean Nicolas Westenberg; Marc Vogel; R Michael Krausz Journal: Harm Reduct J Date: 2021-02-24