Clinical and psychosocial outcomes by sex among individuals prescribed buprenorphine-naloxone (BUP-NX) or extended-release naltrexone (XR-NTX) for opioid use disorder.

BACKGROUND AND OBJECTIVES: Limited research has explored sex differences in opioid use disorder medication (MOUD) treatment outcomes. The purpose of this study was to examine MOUD initiation onto buprenorphine-naloxone (BUP-NX) versus extended-release naltrexone (XR-NTX) by sex, and sex differences in clinical and psychosocial outcomes. METHODS: Using data from a 24-week open-label comparative effectiveness trial of BUP-NX or XR-NTX, this study examined MOUD initiation (i.e., receiving a minimum one XR-NTX injection or first BUP-NX dose) and 24-week self-report outcomes. We used regression models to estimate the probability of MOUD initiation failure among the intent-to-treat sample (N = 570), and the main and interaction effects of sex on outcomes of interest among the subsample of participants who successfully initiated MOUD (n = 474). RESULTS: In the intent-to-treat sample, the odds of treatment initiation failure were not significantly different by sex. In the subsample of successful MOUD initiates, the effect of treatment on employment at week 24 was significantly moderated by sex (p = .003); odds of employment were not significantly different among males by MOUD type; females randomized to XR-NTX versus BUP-NX had 4.63 times greater odds of employment (p < .001). Males had significantly lower odds of past 30-day exchanging sex for drugs versus females (adjusted odds ratios [aOR] = 0.10, p = .004), controlling for treatment and baseline outcomes. DISCUSSION AND CONCLUSIONS: Further research should explore how to integrate employment support into OUD treatment to improve patient outcomes, particularly among women. SCIENTIFIC SIGNIFICANCE: The current study addressed gaps in the literature by examining sex differences in MOUD initiation and diverse treatment outcomes in a large, national sample.