Trends in methadone maintenance treatment participation, retention, and compliance to dosing guidelines in British Columbia, Canada: 1996-2006.

Aspects of methadone maintenance treatment (MMT) delivery, particularly daily dosing practices, are associated with longer retention in treatment. Our objective was to identify trends in compliance to MMT dosing guidelines at the population level in British Columbia, Canada, from 1996 to 2006. Analysis of a provincial drug dispensation database identified 31,724 MMT episodes initiated during the study period. The number of patients in treatment increased from 2,827 in 1996 to 9,601 in 2006. Long-term retention (>36 months) was achieved in 20%-25% of all episodes. Compliance to minimally effective dose guidelines, which is independently associated with retention, fell from 2001 to 2006. Accordingly, this decline was mirrored by 12-month retention figures, which fell from 45.9% in 2001 to 40.5% in 2005. Our evaluation has both highlighted the successes of the British Columbia Methadone program and identified aspects that may be improved to ensure safety and maximize the benefits of MMT.