Mediators of Ethnic Differences in Dropout Rates From a Randomized Controlled Treatment Trial Among Latinx and Non-Latinx White Primary Care Patients With Anxiety Disorders.

Disparities in treatment engagement and adherence based on ethnicity have been widely recognized but are inadequately understood. Few studies have examined treatment dropout among Latinx and non-Latinx White (NLW) individuals. Using Andersen's Behavioral Model of Health Service Use (A behavioral model of families' use of health services. 1968; J Health Soc Behav. 1995; 36:1-10) as a framework, we examine whether pretreatment variables (categorized as predisposing, enabling, and need factors) mediate the relationship between ethnicity and premature dropout in a sample of Latinx and NLW primary care patients with anxiety disorders who participated in a randomized controlled trial (RCT) of cognitive behavioral therapy. Data from a total of 353 primary care patients were examined; 96 Latinx and 257 NLW patients participated. Results indicated that Latinx patients dropped out of treatment more often than NLW patients, resulting in roughly 58% of Latinx patients failing to complete treatment compared with 42% of NLW, and approximately 29% of Latinx patients dropping out before engaging in modules related to cognitive restructuring or exposure, relative to 11% of NLW patients. Mediation analyses suggest that social support and somatization partially explained the relationship between ethnicity and treatment dropout, highlighting the importance of these variables in understanding treatment disparities.