Universal Health Coverage of Opioid Agonist Treatment in Norway: An Equity-Adjusted Economic Evaluation

Background Detailed information on the efficiency of health services targeting opioid use disorder (OUD) and treatment with opioid agonist treatment (OAT) is sparse. Many countries, including Norway, are still falling short of universal health coverage (UHC) of OAT. This study aims to evaluate the incremental lifetime costs and effects of treating OUD with OAT as compared to no OAT in Norway and scaling up the treatment to a universal coverage level using equity-adjusted health economic evaluations. Methods We conducted cost-utility and budget impact analyses and constructed a two-state Markov model to compare the lifetime costs and outcomes among patients with OUD with and without OAT. Model inputs were derived from routine health information systems and the literature, with costs reported in 2023 Norwegian Kroner (NOK). The analyses were conducted from a Norwegian extended health-service and societal perspectives, with a lifetime time horizon. Quality-adjusted life years (QALYs) was the metric of health benefits. Outcomes were reported as incremental cost-effectiveness ratios (ICERs). The willingness-to-pay (WTP) threshold was equity-adjusted according to the future prognostic healthy life year loss method in Norway (severity of disease criterion), which is sensitive to the size of future undiscounted healthy life year loss due to the affected conditions. The WTP threshold is NOK 825,000 per QALY gained in Norwegian policy for conditions with undiscounted future QALY loss > 20. Uncertainty in the parameters and robustness of the results were assessed with one-way and probabilistic sensitivity analyses and scenario analyses. Findings The mean results from probabilistic sensitivity analysis estimated that OAT was associated with 3.03 additional discounted QALYs gain and incremental lifetime discounted cost of NOK 1.45 million, leading to an ICER of NOK 479,099 per QALY gained when compared with not providing OAT, with the extended health-service perspective. From a societal perspective, OAT was cost-saving, i.e. OAT produced greater health benefits while resulting in lower overall societal costs compared to no OAT. The mean undiscounted future health loss was estimated to be 21.34 QALYs for the Norwegian patient group with OUD. A total 5-year budget increase of NOK 1.208 billion was estimated if OAT was going to be scaled up from the current coverage level of 70% to UHC. Compared with the current coverage, 100% coverage of OAT was associated with an additional lifetime cost of NOK 4.332 billion but also an additional 6760 QALYs gained. Conclusion Our analysis suggests that OAT is cost-effective in Norway and has the potential to be cost-saving from a societal perspective. Therefore, Norwegian policy should consider scaling up treatment to extend the coverage of OAT.