Purpose

We examined the impact on geographic distribution of medications to treat opioid use disorder (MOUD) in Oregon after the Comprehensive Addiction and Recovery Act (CARA) was implemented in February 2017 to include nurse practitioner (NP) prescribers.

Methods

We conducted interrupted time series analysis with linear regression on prescriptions dispensed for buprenorphine used for MOUD in the Oregon Prescription Drug Monitoring Database written by physician (MD/DO) and NP prescribers January 1, 2016, to December 31, 2018. We analyzed total prescriptions by prescriber type and pharmacy ZIP Code using STATA 16.1.

Findings

From January 1, 2016, to December 31, 2018, 420,765 eligible prescriptions were written by waivered MD/DO and/or NP prescribers. Prior to CARA, buprenorphine use was increasing steadily at 140 prescriptions per month (95% CI: 78-201; P < .01). Following CARA, dispensing increased by 88 prescriptions per month (95% CI: 23-152; P = .01). The absolute number increased in rural areas immediately after CARA implementation (368 prescriptions; 95% CI: 124-613; P < .01). NP contribution to total buprenorphine prescribing increased significantly in both urban and rural areas (0.44% per month [95% CI: 0.30%-0.57%; P < .01] and 0.74% per month [95% CI: 0.62%-0.85%; P < .01]). The contribution of NPs had a particularly large impact for very rural (frontier) areas, where NPs provided 36% of all buprenorphine prescriptions by the end of 2018.

Conclusion

Changes in federal law regarding MOUD had a positive impact on both supply and geographic distribution in Oregon, particularly in frontier areas comprising 10 of 36 counties (27%).