Estimating the Direct Costs of Outpatient Opioid Prescriptions: A Retrospective Analysis of Data from the Rhode Island Prescription Drug Monitoring Program

BACKGROUND: Overuse and misuse of prescription opioids is associated with increased morbidity and mortality and places a significant cost burden on health systems. OBJECTIVE: To estimate annual statewide spending for prescription opioids in Rhode Island. METHODS: A cross-sectional study of opioids dispensed from retail pharmacies using data from the Rhode Island Prescription Drug Monitoring Program (PDMP) was performed. The study sample consisted of 651,227 opioid prescriptions dispensed to 197,062 patients between January 1, 2015, and December 31, 2015. The mean, median, and total cost of opioid use was estimated using prescription dispensings and patients as units of analysis. A generalized linear model with gamma distribution with an identity link function, and separately with a log link function, was used to estimate the absolute and relative differences in per-patient annual adjusted average opioid prescription cost, respectively, by potential predictors. RESULTS: The estimated 2015 annual expenditure for opioid prescriptions in Rhode Island was $44,271,827. The average and median costs of an opioid prescription were $67.98 (SD $210.91) and $21.08 (quartile 1 to quartile 3 = $7.65-$47.51), respectively. Prescriptions for branded opioid products accounted for $17,380,279.05, which was approximately 39.3% of overall spending, although only 6% of all opioids dispensed were for branded drugs. On average, patients aged 45-54 years and 55-64 years had overall adjusted spending for opioids that were 1.53 (95% CI = 1.49-1.57) and 1.75 (95% CI = 1.71-1.80) times higher than patients aged 65 years and older, respectively. Per patient Medicaid and Medicare average annual spending for opioid prescriptions were 1.19 (95% CI = 1.16-1.22) and 2.01 (95% CI = 1.96-2.06) times higher than commercial insurance spending, respectively. Annual opioid prescription spending was 2.01 (95% CI = 1.98-2.04) and 1.50 (95% CI = 1.45-1.55) times higher among patients who also had at least 1 dispensing of a benzodiazepine or sympathomimetic stimulant, respectively. Average total spending for prescription opioids per patient increased with the average daily dosage: from 3-fold for patients using 50-90 morphine milligrams equivalent (MME) daily to 22-fold for those receiving 90 or more MME daily compared with those receiving less than 50 MME daily. CONCLUSIONS: This study provides the first estimate of the statewide direct cost burden of prescription opioid use using PDMP data and standardized pricing benchmarks. Total annual cost increased with age up to 65 years, mean daily dose, and concurrent use of benzodiazepines or stimulants. Commercial insurance bore the majority of the cost of prescription opioid use, but cost per patient was highest among Medicare beneficiaries. In addition to reducing harms associated with opioid overuse and misuse, substantial cost savings could be realized by reducing unnecessary opioid use, especially among middle-aged adults.