Obstructive sleep apnea is associated with risk for sudden unexpected death in epilepsy (SUDEP) using rSUDEP-7.

Background And Objective: Evaluate relationships between PSG-confirmed OSA and SUDEP risk using the revised SUDEP Risk Inventory (rSUDEP-7).

Methods: Identified adults with epilepsy (AWE) who underwent PSG 2004-2016 at Cleveland Clinic. OSA was defined as apnea-hypopnea index (AHI)- ≥-5/h sleep; moderate/severe OSA as AHI≥15. SUDEP risk was assessed using rSUDEP-7: higher rSUDEP-7 score, greater SUDEP risk. Associations between rSUDEP-7 score and OSA groups (AHI≥15 vs. <15) were evaluated using Wilcoxon rank-sum tests and multivariable linear models adjusting for age, sex, BMI, and smoking status. Spearman correlations measured relationships between rSUDEP-7 score with AHI and oxygen desaturation indices (ODI).

Results: OSA was present in 134 (62.6 %) of 214 AWE; moderate/severe in 75 (35 %). AWE with AHI≥15 were more likely to be male and older, had higher BMI, greater frequency of tonic-clonic seizures (TCS), longer epilepsy duration, and more likely to have drug-resistant epilepsy (DRE) and sleep-related seizures (all p< 0.05). The median rSUDEP-7 score was 1 (0,3) but 37.4 % had a score ≥3 (high SUDEP risk), and 11.7 % ≥5 (highest SUDEP risk). rSUDEP-7 scores were higher in those with AHI≥15 (3 vs. 1, p = 0.001). Higher AHI and ODI 3% positively correlated with rSUDEP-7 (p=0.002 and p=0.016) while SpO nadir negatively correlated with rSUDEP-7 (p=0.007). After adjustments, AWE with AHI≥15 had mean rSUDEP-7 score 1.14 points (95% CI 0.55-1.72, p<0.001) higher than those with AHI<15.

Discussion: AWE with PSG-confirmed moderate/severe OSA especially those who are older and have GTC had higher rSUDEP-7 scores potentially increasing their risk for SUDEP. Our findings support routine screening for OSA in AWE. Further studies confirming the significance and impact of OSA on SUDEP risk are needed.