Mortality related to methadone maintenance treatment in Stockholm, Sweden, during 2006-2013

Background: Methadone maintenance treatment (MMT) of opiate addiction was introduced in Sweden 50 years ago. The first Swedish programs were modeled after the original Dole and Nyswander program, with strict criteria for admittance into treatment, and have been shown to have positive effects on social and health variables, including mortality. During the last 11 years, there have been a number of changes in the regulations controlling MMT-programs in Sweden, and the criteria for admittance are now much less strict compared to previous ones. This study aims to characterize the current MMT-programs with respect to mortality and to compare the results to those obtained in earlier periods. Methods: Persons entering into treatment in Stockholm county, between 2006 and 2011, were followed until September 2013 or until death occurred. Death rates for periods in treatment and out of treatment were determined and compared to rates for the general population. Proportional hazards models with treatment status as time-varying covariate were fitted to the data. A competing risk analysis was made to investigate the effects of MMT on drug-related mortality as compared to mortality from other causes. Mortality data for earlier periods were retrieved from the literature. Results: A total of 441 persons entered MMT during the time period. Of these 67 died during follow-up, the death rate being almost twenty times higher than in the general population. Not being in treatment was associated with a significantly increased hazard of dying (hazard ratio: 2.1, 95% confidence interval: 1.3-3.4). The hazard ratio was mainly increased for drug-related deaths (hazard ratio: 4.4 (2.1-9.2)). Conclusions: Mortality rates among persons who entered MMT-programs in Stockholm during 2006-2011 were not increased compared to persons in treatment twenty years ago. The mortality was significantly increased during periods off treatment. Changes in regulations that minimizes the time off treatment are therefore likely to reduce the mortality rates among clients of MMT-programs. (C) 2016 Elsevier Inc. All rights reserved.