Racial Disparities in Outpatient Substance Use Disorder Treatment Completion: Trends and Changes from 2004 to 2024.

Racial disparities have been found in outpatient substance use disorder (SUD) treatment completion rates. Improvements in access to treatment have sought to decrease these disparities and increase treatment engagement and success. To understand outcomes among different racial groups across time, we assessed (1) completion rates, (2) racial representation among patients who have completed treatment, (3) general representation of racial groups within treatment, and (4) treatment length between 2004 and 2024. "Completion" is defined as "meeting all treatment goals". Chi-squared analyses suggest significant differences among racial groups within the completed (x215=158.0, p=<0.001), not-completed (x215=561.75, p=<0.001), and other (x215=186.19, p=<0.001) groups across time. Asian and Other/Multiracial patients experienced the greatest improvement in both representation within treatment overall and proportional representation within the "completer" group over time, despite their overall completion rates fluctuating. White and Black/African American patients decreased in representation, completion rates, and representation in the "completer" group over time, with a peak in 2004-2009. In terms of length of stay, White patients remained in treatment the longest across time, F(5, 4198) = 24.605, p < 0.011, and treatment length increased for other racial groups. While disparities in completion rates decreased and racial representation in treatment increased, discrepancies persist. We discuss these findings within the context of evolving patient populations and changes in treatment provision (e.g., harm reduction frameworks).