LAUSR

OBJECTIVES The purpose of this longitudinal cohort study was to examine the variables that influence health-related quality of life (HRQOL) after epilepsy surgery in children. We examined whether treatment type (surgical vs. medical therapy) and seizure control are related to other variables that have been shown to influence HRQOL, namely depressive symptoms in children with epilepsy or their parents, and the availability of family resources. METHODS In total, 265 children with drug-resistant epilepsy were recruited from eight epilepsy centres across Canada at the time of their evaluation for candidacy for epilepsy surgery and were assessed at baseline, six-month, one-year and two-year follow-up. Parents completed the Quality of Life in Childhood Epilepsy Questionnaire (QOLCE-55) and measures of family resources and depression; children completed depression inventories. Causal mediation analyses using natural effect models were used to evaluate the extent to which the relationship between treatment and HRQOL was explained by seizure control, child and parent depressive symptoms, and family resources. RESULTS Overall, 111 children underwent surgery and 154 were treated with medical therapy only. The HRQOL scores of surgical patients were 3.4 points higher (95% CI -0.2, 7.0) relative to medical patients at the two-year follow-up after adjusting for baseline covariates, with 66% of the effect of surgery attributed to seizure control. Child or parent depressive symptoms and family resources had negligible mediation effects between treatment and HRQOL. The effect of seizure control on HRQOL was not mediated by child or parent depressive symptoms, nor family resources. SIGNIFICANCE The findings demonstrate that seizure control is on the causal pathway between epilepsy surgery and improved HRQOL in children with drug-resistant epilepsy. However, child and parent depressive symptoms and family resources were not significant mediators. The results highlight the importance of achieving seizure control to improve HRQOL.