It’s generally accepted that medication-assisted treatment (MAT) with methadone or buprenorphine is more effective than nonpharmacologic treatment in opioid use disorder (OUD).
But what about the relative merits of methadone and buprenorphine in OUD? Important differences exist between the two medications in several key areas: underlying pharmacologic actions, dosing schedule, treatment-related resources needed, and costs of treatment, “making it important for all stakeholders to understand the relative costs and benefits of each,” according to the authors of a study recently published in the Journal of Substance Abuse Treatment.
“A Comparison of Adherence, Outcomes, and Costs Among Opioid Use Disorder Medicaid Patients Treated With Buprenorphine and Methadone: A View From the Payer Perspective,” begins with a summary of what is known, or postulated, about the two medications:
| Methadone | Buprenorphine |
|---|---|
| Schedule II; resource-intensive; dispensed only in licensed/accredited OTPs | Schedule III; more accessible to rural patients; available through primary care physicians or waivered physician extenders |
| Some evidence: more likely than buprenorphine to retain patients in treatment and/or prevent relapse | Some evidence: patients more likely to relapse, or have shorter treatment episodes, than methadone patients |
| Patients are slightly more likely to have a drug-related overdose, especially initially | Programs spend fewer health care dollars, use fewer health care resources |
Lead author Suzanne Kinsky, MBA, PhD, and her team of investigators, most of whom are affiliated with the University of Pittsburgh Medical Center (UPMC), were especially interested in the comparative performance of methadone and buprenorphine in three critical areas:
- Reducing the use of illicit opioids
- Reducing the risk of drug-related overdose (OD)
- Lowering overall health care costs
They assessed “adherence, costs, and emergency department (ED) nonfatal drug-related overdose outcomes” among a sample of Medicaid members, examining the data from the payer perspective.
Study Group
Enrollees were Pennsylvania residents covered by Medicaid, the primary funding source for MAT in the geographic area. Enrollees also received physical and behavioral coverage through the UPMC Health Plan.
The authors set up protocols for two analyses—adherence and cost—and selected study group enrollees. Using six months of physical and behavioral Medicaid claims data for newly treated patients, the authors looked at:
- Predictors of adherence
- Differences in adherence between methadone and buprenorphine
- Relationship of adherence to nonfatal drug-related overdose in the ED
- Total cost of care, methadone vs. buprenorphine
Results
Adherence Analysis
The team used the Area Deprivation Index (ADI) to assess adherence. The ADI is a composite of socioeconomic factors; high ADI values indicate areas of high socioeconomic deprivation.
| Participants, Adherence Analysis |
|---|
| Available for analysis: 1,184 Received buprenorphine: 972 Received methadone: 212 |
Definitions of Nonadherence
|
Key Findings
- Only 3.6% of adherent individuals (either treatment) had a nonfatal, drug-related OD in the ED, vs. 13.2% of nonadherent individuals
- Six-month adherence was higher with methadone (49.1%) than with buprenorphine (40.8%), but the difference was not statistically significant
Additional Findings
- A nonfatal ED overdose
- Was less likely in older people, women, and subjects who had adhered for six months*
- Was more common in those who were nonadherent for six months*
- Risk of nonadherence was lower in older individuals and in women*
(In this article, results reported with an asterisk are statistically significant (P ≤ 0.05); results reported without an asterisk do not reach the level of statistical significance.)
Cost Analysis
The “cost of care” represents UPMC’s actual payments. The authors explained that cost was calculated “on a per member per month (PMPM) basis, and covered medical care, behavioral health care, and pharmacy costs.”
| Participants, Cost Analysis |
|---|
| Available for analysis: 692 Received methadone: 125 Received buprenorphine: 567 |
Key Findings
- Although no difference in PMPM was seen between the two treatments, pharmacy costs decreased by $23 in those receiving methadone, but increased by $219 in those receiving buprenorphine*
- In individuals receiving methadone
- PMPM increased markedly—$1,173.50 from baseline—in nonadherent subjects*
- PMPM decreased by $13.27 in adherent subjects*
- In the buprenorphine group
- PMPM increased by $533.20 in adherent subjects*
- PMPM increased by $475.94 nonadherent subjects*
Additional Findings
- In areas with low socioeconomic deprivation, six-month adherence was higher in the methadone group (55%) than in the buprenorphine group (40%)
Authors’ Comments
Although overdose occurred more than 3.5 times as often in participants who were nonadherent, the authors note that the design of the study “cannot rule out important sources of bias.” An example would be unobserved factors leading the individual to stay in treatment and follow safer ways of using opioids. They also cite “conflicting results” that highlight the challenge of measuring and controlling for contextual factors related to opioid use.
Adherence, overdose, and cost. Regarding adherence, there was no difference between methadone and buprenorphine from an overdose standpoint. But from a cost standpoint, the consequences of nonadherence were striking for individuals in the methadone group.
Factors influencing adherence. Adherence to MAT—regardless of treatment group—was a crucial factor. The authors recommended that when considering opioid interventions, health care providers and policy makers weigh factors that can influence adherence—such as age, gender, and neighborhood.
How to effectively address barriers to adherence is an issue that needs investigation, the authors point out, given the “profound and multi-level consequences of nonadherence.” In addition to behavioral and structural interventions, future studies could examine long-acting forms of buprenorphine and their effect on adherence, overdose, and costs.
Conclusion
In closing, the authors noted the need for comparative research on available therapies “so that individuals affected by opioid use, providers, payers, policymakers, and other stakeholders can make informed decisions about appropriate interventions. This study finds that there are complex relationships between MAT adherence, risk of nonfatal overdose, and cost of care.”
Reference
Kinsky S, Houck PR, Mayes K, et al. A comparison of adherence, outcomes, and costs among opioid use disorder Medicaid patients treated with buprenorphine and methadone: A view from the payer perspective [Epub ahead of print May 31, 2019]. J Subst Abuse Treat. 2019;104:15-21. doi: 10.1016/j.jsat.2019.05.015