A population-based study on the risk of prescription opioid abuse in patients with chronic opioid use and cost-effectiveness of prescription drug monitoring program using a patient simulation model in South Korea

Background: Concerns regarding the burden of inappropriate opioid use are growing. We examined the association between prescription opioid abuse and patient characteristics and estimated the cost-effectiveness of the prescription drug monitoring program (PDMP) implemented in South Korea, considering patient-level information. Methods: A retrospective cohort study was conducted to explore the association between opioid abuse and patient characteristics using the National Health Insurance Service–National Sample Cohort (NHIS-NSC) database. We selected non-cancer patients with chronic opioid use and investigated the incidence of opioid abuse between 2010 and 2015. The association between opioid abuse and patient characteristics was assessed using the Cox proportional hazards model. The cost-effectiveness of the PDMP was assessed using discrete event simulation (DES) with a time horizon of 30 years from a societal perspective. Time-to-event data and event costs were obtained from the NHIS-NSC database. The abuse rate was adjusted for each patient based on the baseline characteristics and history of abuse experienced in the model. Program effectiveness, program costs, and health-state utilities were obtained from the published literature. The incremental cost-utility ratio (ICUR) was estimated at a discount rate of 5% for both costs and quality-adjusted life-years (QALYs). Results: We identified 22,524 patients with chronic opioid use in the NHIS-NSC database. Every one-year increase in age (hazard ratio: 1.002 [95% CI: 1.000–1.003]), medical aid program (1.130 [95% CI: 1.072–1.191]), high Charlson Comorbidity Index (1.054 [95% CI: 1.044–1.065]), and history of opioid abuse (1.501 [95% CI: 1.391–1.620] and 3.005 [95% CI: 2.387–3.783] for 1–2 and ≥3 abuse events, respectively) significantly increased the risk of opioid abuse. In the DES, the PDMP was cost-effective, with an estimated ICUR of $2,227/QALY, which was most affected by the program's effectiveness. Conclusion: Patient characteristics and history of opioid abuse affected the risk of opioid abuse. Considering patient-level information, the PDMP implemented in South Korea is likely to be cost-effective.