In the US, Few Randomized Trials for Substance Use Treatment Adequately Consider Racial or Ethnic Factors

Despite observational data demonstrating that Black and Latinx populations experience worse substance use disorder (SUD)-related outcomes relative to white persons, few randomized controlled trials (RCTs) have examined differences in SUD outcomes by race/ethnicity or underlying social determinants of health. Researchers conducted a systemic review of RCTs conducted in the US (published 1995–2019) that examined non-nicotine SUD outcomes (i.e., treatment initiation, treatment engagement, and substance use) by race or ethnicity. They aimed to determine whether SUD intervention effectiveness varies by race or ethnicity, or by intervention type or substance used within Black and Latinx populations.

• Of 5204 RCTs identified, 50 met inclusion criteria.
• Twenty-four studies reported outcomes by race or ethnicity. Nine studies found a significant main effect of race or ethnicity, including the fact that Black and Latinx participants had poorer SUD treatment retention and abstinence outcomes compared with white participants.
• Of the 15 studies that evaluated participants’ baseline social determinants of health (e.g., socioeconomic status, education) by race/ethnicity, 100% found significant differences. Few of these studies, however, accounted for these differences in primary analyses.
• Within studies focusing on Black (n=12) or Latinx (n=12) participants, interpretation of differences between intervention type and substance used was limited by the small number of studies.

Comments: Few RCTs appropriately include racial or ethnic minorities, or adequately evaluate whether baseline differences in social determinants of health by race or ethnicity influence study results. Future RCTs examining SUD outcomes should focus on both improved inclusion of racial and ethnic minorities, as well as evaluation of the impact of social determinants of health on treatment outcomes among these populations.

Carrie M. Mintz, MD

Reference: Jordan, A, Quainoo, S, Nich, C et al. Racial and ethnic differences in alcohol, cannabis, and illicit substance use treatment: a systematic and narrative synthesis of studies done in the USA. Lancet Psychiatry. 2022; 9:660–674.