Effects of a remotely delivered group-format epilepsy self-management program on adverse health outcomes in vulnerable people with epilepsy: A causal mediation analysis

•A novel self-management approach positively impacted outcomes in people with epilepsy.•20-30 % of improvements in adverse outcomes were mediated by improvements in mood.•Results encourage closer attention to depression severity and quality of life in epilepsy. People with epilepsy frequently experience negative health events (NHEs), such as emergency room visits or hospitalizations for epilepsy-related complications despite significant advances in care. We developed a novel remotely delivered group-format epilepsy self-management program (“Self-management for people with epilepsy and a history of negative health events”; SMART). In a 6-month randomized controlled trial (RCT), SMART participants had significant decreases in NHEs, as well changes in attitudes and behaviors compared to a wait-list (Sajatovic et al., 2018). This secondary analysis from the RCT characterizes the indirect causal effects of SMART on NHE improvements that may be mediated by specific improvements in self-management, self-efficacy, social support, quality of life, and depression symptom severity. Participants were adults with epilepsy and a NHE in the prior 6 months. There were 60 participants in each RCT arm (SMART versus wait-list) and assessments were conducted at baseline, 10 weeks and 24 weeks. The outcome was a binary variable measuring NHE improvement at week 24. A counterfactual-based mediation framework was used to determine whether improvements or changes in attitudes and behaviors at specific time points or across the study period, mediated the impact of SMART on NHE improvements. At week 24, SMART contributed to significant improvements in NHEs compared to those in wait-list (odds ratio = 3.2, p = 0.015). SMART was significantly associated with improvements and changes in aspects of self-management, self-efficacy, quality of life, and depression symptom severity at week 10, and significant improvements between baseline and week 24 in overall self-management and quality of life. Mediation analyses demonstrated that a portion of the effect (∼20-30 %; p < 0.05) of SMART on NHE improvement was also indirectly mediated by early improvements in depression symptom severity and quality of life. This mediation analysis of the SMART intervention demonstrates that in addition to its direct effect on improving NHEs in people with epilepsy, early improvements in depression symptom severity and quality of life indirectly mediated ∼20-30 % of the intervention’s effect. These results d