Secondary analysis of a combined harm-reduction treatment and extended-release naltrexone randomized clinical trial for alcohol use disorder: Differences across race, ethnicity and sex assigned at birth.

Abstract

In a prior randomized clinical trial (RCT), combined pharmacobehavioral harm-reduction treatment improved alcohol outcomes and physical health-related quality of life (PH-QoL). In this secondary analysis, we tested race, ethnicity and sex assigned at birth as predictors and moderators of these effects. Secondary study of a four-arm RCT. Community settings serving people experiencing homelessness in the US Pacific Northwest. Adults aged 21-65 (N = 308) with alcohol use disorder (AUD) who experienced past-year homelessness. In the parent RCT, participants were randomized to brief behavioral harm-reduction treatment for AUD + extended-release naltrexone (HaRT-A + XR-NTX); HaRT-A + placebo; HaRT-A alone, or services-as-usual control. We tested whether baseline outcomes, trial inclusion, data missingness, treatment adherence, side effects, and treatment effects on alcohol frequency, quantity, alcohol-related harm, urinary ethyl glucuronide, and PH-QoL differed by race, ethnicity, and sex assigned at birth. Race, ethnicity and sex assigned at birth were not associated with differential trial inclusion, missingness, treatment adherence or side effects with one exception: the Multiracial/other people of color (POC) group attended fewer HaRT-A sessions than the white group (odds ratio [OR] = 0.49, p = 0.03, 95% confidence interval [CI] [0.25, 0.95]). There were no statistically significant moderators of the behavioral HaRT-A effect; however, Multiracial/other POC race (B = -3.34, p = 0.03, 95% CI [-6.35, -0.34]) and sex assigned at birth (B = 2.43, p = 0.04, 95% CI [0.14, 4.73]) moderated the XR-NTX versus placebo effect on one variable: PH-QoL. Simple slope analysis indicated the Multiracial/other POC group who received placebo showed improvement on PH-QoL (dy/dx = 2.61, p = 0.003, 95% CI [0.91, 4.31]); the XR-NTX group did not (dy/dx = -0.22, p = 0.79, 95% CI [-1.90, 1.45]). Among XR-NTX recipients, the female group (dy/dx = 2.89, p < 0.001, 95% CI [1.53, 4.25]) showed faster improvement rates than the male group (dy/dx = 1.19, p = 0.02, 95% CI [0.23, 2.16]) on PH-QoL. Race, ethnicity and sex assigned at birth were largely not associated with trial inclusion, data missingness, treatment adherence, side effects, or outcomes in a combined harm-reduction treatment and extended-release naltrexone randomised clinical trial for alcohol use disorder (AUD). Although Multiracial/other people of color (POC) participants attended fewer brief behavioral harm-reduction treatment for AUD sessions, they did not differ from white participants on alcohol and physical health-related quality of life outcomes. Among participants receiving extended-release naltrexone (XR-NTX), women showed greater improvement than men on physical health-related quality of life. Compared with white participants, Multiracial/other POC participants who received XR-NTX showed less improvement than those who received placebo. Given their post hoc nature and limited power, findings are hypothesis-generating. They suggest the equitable utility of behavioral harm-reduction treatment and the importance of assessing sociodemographic differences in AUD treatment response.