MACPAC Finds Dropping Prior Authorization Lifted Buprenorphine Use

States that stopped requiring prior authorization for buprenorphine filled 12.8 percent more of the medication per 1,000 Medicaid enrollees with opioid use disorder and recorded fewer opioid-related overdoses, according to a claims analysis MACPAC staff presented to the commission on Thursday. The same analysis found that the share of enrollees in continuous treatment for at least six months fell from 60.2 percent in 2020 to 55.4 percent in 2023.

The findings, presented by Sheila Shaheed and Anupama Warrier at the Medicaid and CHIP Payment and Access Commission's October meeting, land in the middle of a policy argument that has mostly been conducted with anecdotes: whether the paperwork states and managed care plans layer onto addiction medication keeps people out of treatment or protects them from harm.

What the analysis measured

MACPAC and its contractor, Acumen LLC, used a synthetic difference-in-differences design on Transformed Medicaid Statistical Information System claims from calendar years 2019 through 2023. The population was full-benefit, non-dually-eligible Medicaid and CHIP enrollees ages 16 to 64 with a diagnosis of opioid use disorder. States that loosened a specific policy were compared against a weighted combination of states that did not.

Two policies were tested separately: removal of prior authorization for at least one oral buprenorphine-naloxone combination product, and an increase in the daily dosage limit to at least 32 milligrams. Outcomes were the share of enrollees ever filling a prescription, the volume of fills, opioid-related overdoses recorded in health care settings, and opioid-related emergency department visits.

The design has an acknowledged weakness. Only one year of data precedes the policy changes, so the analysts could not test whether treated states were already on a different trajectory before they acted. The claims also do not record whether prior authorization was actually used, only whether it was required on paper, and the review covered fee-for-service drug utilization reports rather than managed care.

Prior authorization: more fills, fewer overdoses

Forty-seven states and the District of Columbia let at least one oral buprenorphine-naloxone product be dispensed without prior authorization in fiscal 2023, up from 41 states in fiscal 2019. Six states changed that rule during the study window — Indiana, Iowa and Michigan in 2020, Colorado and Wyoming in 2022, and Tennessee in 2023.

Across those states, removing prior authorization was associated with a 2.5 percentage point increase in the share of enrollees with at least one fill, an estimate the deck marks as marginally significant at a p-value of 0.081. Fills per 1,000 enrollees with opioid use disorder rose 12.8 percent, which crosses the conventional significance threshold at p=0.030. Opioid-related overdoses fell 0.6 percentage points, also marginal at p=0.086. Emergency department visits moved down 0.3 percentage points with a p-value of 0.614 — in plain terms, no measurable effect.

The effects grew with time. By the end of the third year after a state dropped the requirement, the volume of oral buprenorphine fills was 18.3 percent higher, opioid-related overdoses had fallen 2.0 percentage points and opioid-related emergency visits had fallen 1.2 percentage points, according to the presentation.

MACPAC's interviews with state officials and providers put a number on the friction the policy creates: prior authorization can delay access to medication by several days, and some of the people interviewed described it as a less effective tool than retrospective review or point-of-sale safety edits.

The number moving the wrong way

Treatment continuity is the finding that cuts against the policy story. MACPAC defined it as 180 days of continuous treatment with any form of medication for opioid use disorder — oral or injectable buprenorphine, methadone, or naltrexone — with no gap longer than seven days. Among enrollees who filled at least one oral buprenorphine prescription, the rate climbed to 60.2 percent in 2020 and then declined every year after: 59.5 percent in 2021, 58.2 percent in 2022 and 55.4 percent in 2023.

Over the same period, the share of enrollees with opioid use disorder who used oral buprenorphine rose from 35.5 percent to 39.1 percent. Opioid-related overdose rates in that population went from 6.9 percent in 2019 to a peak of 8.1 percent in 2021 and back to 7.1 percent in 2023; among enrollees with at least one buprenorphine fill, the rate fell from 4.9 percent to 4.4 percent. Emergency department visits followed a similar arc, from 18.7 percent of enrollees with opioid use disorder in 2019 to 16.7 percent in 2023.

The presentation does not explain the continuity decline. It asks commissioners directly for their views on "factors contributing to national declines in MOUD treatment continuity," which makes retention the open question the next phase of the project is meant to address. Getting a first prescription filled and keeping a patient on medication for six months are different problems, and only the first one appears to respond to removing paperwork.

Dosage caps and the 32-milligram line

The second policy under review concerns how much buprenorphine a state will pay for. Thirty-eight states limited daily dosing to 16 or 24 milligrams in fiscal 2023, and the Food and Drug Administration issued a notice in December 2024 clarifying that neither figure should be read as a maximum and that doses above 24 milligrams may be appropriate for some patients. Two states still capped daily doses at 16 milligrams as of the 2023 claims data.

Raising the limit to at least 32 milligrams was associated with a 1.2 percentage point decline in opioid-related emergency department visits, significant at p=0.020, and no detectable change in overdoses or in the share of enrollees getting an additional fill. The analysts noted that the estimate for overdoses carries a wide confidence interval and should not be read as proof that higher doses are risk-free — only that the policy change did not produce a measurable increase.

Providers interviewed for the project described dosage caps as a barrier for patients who need higher doses to stabilize, warning that under-dosing can destabilize people and put them at risk of relapse.

Where the analysis goes next

MACPAC is an advisory body, not a regulator. Staff told commissioners they may return with draft policy options in January, and the literature review, interviews and claims work will be synthesized into a chapter of the commission's June 2027 report to Congress.

The statutory backdrop is already set: as of fiscal 2020, the Consolidated Appropriations Act of 2024 requires state Medicaid programs to cover every form of FDA-approved medication for opioid use disorder along with counseling and behavioral therapies. What states retain is the discretion to decide how much paperwork stands between a patient and the pharmacy counter, and the MACPAC analysis is the first multi-state claims estimate of what that discretion costs and buys.

For patients, the practical question is narrower than the policy debate. Medicaid covers roughly half of nonelderly adults with opioid use disorder, and buprenorphine treatment remains the most widely used medication in that population — 57 percent of enrollees receiving medication in fiscal 2022. Medication-assisted treatment programs that pair the prescription with counseling and retention support address the continuity problem the claims data surfaced. The commission's earlier look at buprenorphine fills and the Medicaid cuts now taking effect covers the financing side of the same question.