Abstracts

Rationale: Sleep disturbances have been reported to be highly prevalent among persons with epilepsy (PWE), especially among those not well controlled on medications. ‘Epilepsy related deaths’ are also commoner than other causes, among PWE, with sudden unexpected death in epilepsy (SUDEP) remaining an extremely serious concern. Most SUDEP events occur during sleep. Excessive daytime sleepiness (EDS) is among the most common sleep related problems encountered among PWE and can be measured using the Epworth sleepiness scale (ESS) , the most commonly used,  validated tool. The SUDEP-7 inventory, in turn, has been used for SUDEP risk assessment. While EDS in epilepsy is often multi-factorial, it is an important indicator of poor nighttime sleep quality.  This study was conducted to evaluate the relationship between EDS and SUDEP risk in PWE._x000D_
Methods: Consecutive patients diagnosed with active epilepsy at our tertiary care Canadian epilepsy clinic, during a three-year study period, formed the study population. Those with serious co-morbidities and those with incomplete data were excluded. The SUDEP-7 Inventory was applied and score calculated for all eligible PWE, following a detailed chart review. A database was created to collect information on demographics, epilepsy diagnosis and details, and the SUDEP-7 scores. Patients were then stratified into 2 groups, those with ESS scores greater than or equal to 10 (EDS), and those with scores less than 10 (no EDS). Based on the SUDEP-7 scores, the study population was also categorized into ‘high risk’ (4 or more) and ‘low risk’ (less than 4) groups. A correlational relationship between EDS and SUDEP risk was then determined using 2x2 table statistics and application of Chi square test. _x000D_
Results: Of the 304 total eligible PWE, 190 (93 males, 97 females, mean age of 40.16 ± 16.10) had 10 or higher ESS scores (EDS group), while 114 (53 males, 61 females, mean age of 41.85 ± 15.98) had ESS scores lower than 10 (no EDS group). In the EDS group, 17 (8.95%) could be categorized as "high SUDEP risk" and 173 were "low SUDEP risk." In comparison, 2 patients (1.75%) in the 'no EDS' group, could be categorized as high SUDEP risk with 112 being low SUDEP risk. This SUDEP risk difference was hence significantly higher in the EDS group (risk ratio 5.1, 95% confidence interval (1-22) [p=0.0047])._x000D_
Conclusions: In this retrospective chart review-based study, EDS was found to be highly associated with higher SUDEP risk, as measured using the SUDEP-7 inventory. As EDS could represent underlying night-time sleep disturbances, among other factors, the observations from this study highlight the need for more detailed sleep assessment in PWE to obtain more reliable information on SUDEP risk stratification._x000D_
Funding: None