Pharmacotherapies for treatment of opioid use disorder: a narrative review and cost-effectiveness analysis

Opioid use disorder (OUD) has become a global concern with the rapid increase in the use of illicit and prescription opioids. North America is in the midst of the opioid crisis, which requires effective (both clinically and economically) treatment interventions. Several evidence-based treatment options are available for the treatment of OUD. However, little is known about patients’ perspectives on the pharmacotherapies used for OUD treatment. Additionally, with the advent of novel and more expensive treatment options, an economic evaluation against conventional treatment is warranted. The aim of this thesis is two-fold: first, to conduct a narrative review of patients’ perceptions and experiences with OUD pharmacotherapies and second, to compare the cost-effectiveness of the newer pharmacotherapies with conventional treatments. The thesis follows a manuscript style with the following chapters: Chapter 1 provides an introduction; Chapter 2 provides a narrative review of patients’ perceptions and experiences with the pharmacotherapies for OUD treatment; Chapter 3 is the cost-effectiveness analysis of the newer pharmacotherapies compared against the usual treatment; and, Chapter 4 concludes. In the narrative review, we conducted a systematic search of relevant literature on patients’ perceptions and experiences with OUD pharmacotherapies. The data are coded to develop overarching themes. The findings are narratively described under these themes for the outcomes of perceptions and experiences. We critically appraised the included studies to assess their quality. We found evidence of both patient-reported positive and negative aspects of the treatments. Other key findings of this review study are lack of patient knowledge on the available treatment options, many patients seeking harm reduction treatment strategy with opioid agonist treatment (OAT), while others seeking abstinence-based treatment interventions, and the role of patient inclusive treatment decisions to optimize treatment outcomes. In the cost-effectiveness study, we compared five treatment strategies using the US healthcare perspective: 1) methadone-lofexidine for detoxification and buprenorphine-naloxone for maintenance; 2) methadone-lofexidine for detoxification and extended-release naltrexone for maintenance; 3) buprenorphine-naloxone for detoxification and extended-release buprenorphine for maintenance; 4) buprenorphine-naloxone for detoxification and maintenance (i.e., usual treatment); and, 5) no treatment. Effectiveness outcomes are presented in quality-adjusted life-years (QALYs), treatment retention and opioid-free days. Detoxification with methadone-lofexidine and subsequent buprenorphine-naloxone maintenance yield greater effectiveness than usual treatment but are not cost-effective at the willingness-to-pay threshold of US$100,000 per QALY gained due to the high cost of lofexidine. Usual treatment with buprenorphine-naloxone is found to be cost-effective at the conventional willingness-to-pay threshold