A new study published in JAMA Network Open has uncovered racial disparities in the dosing of medications used to treat opioid use disorder (OUD) within clinical trial settings. The research indicates that Black patients consistently received lower doses of both buprenorphine and methadone compared to their White counterparts during the initial weeks of treatment. This finding raises concerns about the generalizability of clinical trial results and the potential for unequal treatment outcomes.
The cohort study, which analyzed data from three National Institute on Drug Abuse Clinical Trials Network trials conducted between 2006 and 2017, included 1748 participants. The analysis focused on the first four weeks of treatment, a critical period for dose adjustment. The study revealed that Black patients received significantly lower mean doses of both buprenorphine and methadone compared to White patients. Specifically, by week four, Black patients received buprenorphine doses 2.5 mg lower (95% CI, -4.6 to -0.5) and methadone doses 16.7 mg lower (95% CI, -30.7 to -2.7) after adjusting for age and sex.
Key Findings on Dosing Disparities
The study also examined the percentage of patients receiving higher doses of medication, defined as ≥16 mg for buprenorphine and ≥60 mg for methadone. The results showed that Black patients were 16.9 percentage points less likely to receive a higher dose of medication compared to White patients (95% CI, -31.9 to -1.9) in week four. In contrast, Hispanic patients received buprenorphine doses similar to White patients, though methadone doses were sometimes lower.
"These findings suggest the need for research to understand mechanisms associated with disparities in OUD treatment quality and interventions to reduce them," the authors stated. They also noted that higher doses of OUD medications are generally more effective, suggesting that these dosing disparities could contribute to poorer treatment outcomes for Black patients.
Potential Causes and Implications
The researchers suggest that the observed disparities may stem from a combination of factors, including structural, institutional, and interpersonal racism. Differences in documented severity of baseline withdrawal symptoms between Black and White patients may also play a role, potentially influencing clinicians' dosing decisions. The study points out that even when clinicians follow treatment recommendations, disparities can be perpetuated if underlying biases affect the assessment and reporting of symptoms.
Davida M. Schiff, MD, MSc, from MassGeneral Hospital for Children, commented on the study's findings in an accompanying editorial, noting that the subjective nature of clinician observations of certain opioid withdrawal symptoms might contribute to disparities in severity grading. Schiff suggested that underreporting or underappreciation of withdrawal symptoms and reported cravings due to structural and historical factors may explain downstream disparities in treatment retention and adverse opioid outcomes.
Addressing Disparities in OUD Treatment
The study authors emphasize the need for interventions to address these disparities, including campaigns to improve awareness of dosing recommendations, training for facility staff on mitigating the impact of interpersonal racism, and community-specific interventions to address mistrust of OUD treatment. Further research is crucial to identify the driving mechanisms behind these disparities and to develop strategies that ensure equitable access to effective OUD treatment for all patients.
Limitations and Future Directions
The study acknowledges several limitations, including the age of the data (collected between 2006 and 2017) and the relatively small sample size of non-Hispanic Black patients. The authors also note that they lacked the data to investigate specific mechanisms for dosing disparities or to explore potential remedies. Future research should focus on addressing these limitations and further exploring the complex factors that contribute to racial and ethnic disparities in OUD treatment.
