Comorbidities and predictors of health-related quality of life in Dravet syndrome

Purpose: Health-related quality of life (HRQOL) has emerged as a widely accepted measure to evaluate how chronic disease impacts on an individual's physical, social, and mental well-being. There is a paucity of data focusing on HRQOL in specific epilepsy syndromes and their associated needs. In this study our aim was to describe the comorbidities and disease-related predictors for HRQOL in Dravet syndrome, an epileptic encephalopathy, with defined genetic etiology. We anticipate that this will help us to better recognize and understand the needs of children and families and aid treatment planning in this severe epilepsy syndrome. Methods: One hundred sixty-three individuals with Dravet syndrome and their families participated in the study. Detailed clinical and demographic information was available for each case. HRQOL was evaluated with two epilepsy-specific instruments, the Impact of Pediatric Epilepsy Scale (IPES) and the Epilepsy & Learning Disabilities Quality of Life Questionnaire (ELDQOL); a generic HRQOL instrument; the Pediatric Quality of Life Inventory (PedsQL); and a behavioral screening tool, the Strength and Difficulties Questionnaire (SDQ). Key Findings: HRQOL was significantly lower for children with Dravet syndrome compared to normative data (p < 0.001). A cross-sectional evaluation of measures across different age groups revealed that PedsQL generic core and cognitive function scales decreased in older age categories, indicating worse HRQOL (p < 0.001). Assessment of epilepsy severity demonstrated that symptoms were rated very severe in 10 (6%) of 162 cases, somewhat severe in 78 (48%) of 162, moderate in 51 (32%) of 162, and mild in 23 (14%) of 162 cases. The epilepsy severity correlated significantly with the IPES total impact score (r = 0.466, p < 0.001, n = 162). The IPES total impact scores in the Dravet group (n = 162) were significantly higher than scores measured in the original validation sample of epileptic children with and without learning difficulties (+/- SD) (21.0 +/- 8.7 vs. 11.6 +/- 5.4, t = 8.95, p < 0.001, n = 46). On the SDQ, 35% of children scored in the abnormal range for "conduct problems," 66% for "hyperactivity/inattention," and 76% for "peer relationships." Regression analysis revealed that young age at seizure onset (p = 0.019), presence of myoclonic seizures (p = 0.029), motor disorder (p = 0.048), learning difficulties (p = 0.002), epilepsy severity (p < 0.001), and behavioral difficulties (p < 0.001) each independently predicted poorer HRQOL. Behavioral problems such as hyperactivity/inattention were the strongest predictors of poorer HRQOL. Significance: This is the first comprehensive study of HRQOL in an etiologically well-defined epilepsy syndrome. HRQOL in Dravet syndrome depends on a series of independent factors including seizure control, behavior, cognitive, and motor problems. Identification of specific comorbidities in Dravet syndrome will facilitate a distinct and multidisciplinary approach to management, addressing seizure control, behavior problems, cognitive difficulties, and motor impairment.