Spatial access to opioid treatment program and alcohol and cannabis outlets: analysis of missed doses of methadone during the first, second, and third 90 days of treatment

Background: The burden of access to opioid treatment programs (OTPs) may change as clients become eligible for take-home privileges. Our previous study showed clients who lived more than 10-miles away from an OTP were more likely to miss methadone doses during the first 30 days of treatment. Proximity to alcohol and cannabis outlets may also negatively influence treatment adherence. Objective: To examine the association between access to this OTP, alcohol and cannabis outlets, and the number of missed methadone doses during the first, second, and third 90 days of treatment. Methods: The number of missed methadone doses was calculated for 752, 689, and 584 clients who remained in treatment, respectively, for at least 3, 6, and 9 months (50% female). Distance between client’s home and the OTP, alcohol, and cannabis outlets was measured. Generalized linear models were employed. Results: Shorter distance from a client’s residence to the OTP was associated with a decreased number of missed methadone doses during the first 90 days of treatment. Shorter distance to the closest cannabis retail outlet was associated with an increased number of missed methadone doses during the first and second 90 days of treatment. Shorter distance to the closest off-premise alcohol outlet was associated with an increased number of missed methadone doses during the third 90 days of treatment. Conclusions: Improving spatial accessibility of OTPs are essential to ensure treatment opportunities are available for individuals so affected. Exploring to what extent residing in areas that facilitate alcohol and cannabis availability can influence treatment adherence is warranted.