Rogeberg O, et al. - Researchers conducted a population-based prospective cohort study with the aim to determine the causal effects of a national opioid agonist treatment (OAT) program on population level drug fatalities.

• Data concerning supply-driven variation in treatment uptake across cohort-age groups generated by the introduction and scale-up of a national OAT program, were utilized.

• A total of 5,634 drug-related overdose deaths and the introduction of the Norwegian OAT program in 1998 and its initial growth period, reaching 12,286 ever-treated recipients by 2016, were included in this work.

• As per estimates, in the absence of OAT, there would have been an additional 887 deaths (95% credibility interval (CI) 265-1,563), which implies an avoidance of one death per 111 (95% CI: 61-342) treatment-exposed person-years.

• Overall, substantial and plausibly causal reductions were recorded in drug fatalities in correlation with the introduction and rapid scale-up of a national opioid agonist treatment program in Norway.