Prerandomization withdrawals from a Type 2 diabetes self-care support intervention trial are associated with lack of available support person coparticipant.

Dyadic interventions, involving two persons with a preexisting close relationship, offer the opportunity to activate support persons (SPs) to improve health for adults with chronic conditions. Requiring SP coparticipation can challenge recruitment and bias samples; however, the associations between voluntary SP coparticipation and recruitment outcomes across patient characteristics are unknown. The Family/Friend Activation to Motivate Self-care 2.0 randomized controlled trial (RCT) enrolled adults with Type 2 diabetes (T2D) from an academic health system. Participants were asked-but not required-to invite an SP to coenroll. Using data from the electronic health record we sought to describe RCT enrollment in the setting of voluntary SP coparticipation. In a diverse sample of adults with (T2D) (48% female, 44% minoritized race/ethnicity), most participants (91%) invited SPs and (89%) enrolled with SPs. However, prerandomization withdrawal was significantly higher among participants who did not have consenting SPs than those who did. Females were less likely to invite SPs than males and more Black PWD were prerandomization withdrawals than randomized. Voluntary SP coenrollment may benefit recruitment for dyadic sampling; however, more research is needed to understand if these methods systematically bias sampling and to prevent these unintended biases.