To estimate the incidence of sudden unexpected death in epilepsy (SUDEP) in people with intellectual disabilities in residential care settings and to ascertain the effects of nocturnal seizures and nocturnal supervision on SUDEP risk.Methods
We conducted a nested case-control study reviewing records of all people who died at 2 residential care settings over 25 years. Four controls per case were selected from the same population, matched on age (±5 years) and residential unit. Nocturnal supervision was graded in 3 categories: (1) no supervision; (2) a listening device or a roommate or physical checks at least every 15 minutes; and (3) 2 of the following: a listening device, roommate, additional device (bed motion sensor/video monitoring), or physical checks every 15 minutes. Outcome measures were compared using Mann-Whitney U tests and Fisher exact tests.Results
We identified 60 SUDEP cases and 198 matched controls. People who died of SUDEP were more likely to have nocturnal convulsive seizures in general (77% of cases vs 33% of controls, p < 0.001) and a higher frequency of nocturnal convulsive seizures. Total SUDEP incidence was 3.53/1,000 patient-years (95% confidence interval [CI] 2.73–4.53). The incidence differed among centers: 2.21/1,000 patient-years (95% CI 1.49–3.27) vs 6.12/1,000 patient-years (95% CI 4.40–8.52). There was no significant difference in nocturnal supervision among cases and controls, but there was a difference among centers: the center with a lowest grade of supervision had the highest incidence of SUDEP.Conclusions
Having nocturnal seizures, in particular convulsions, may increase SUDEP risk. Different levels of nocturnal supervision may account for some of the difference in incidence.