Association of prone position with sudden unexpected death in epilepsy.

OBJECTIVE To examine the association between prone position and sudden unexpected death in epilepsy (SUDEP). METHODS We conducted a systematic review and meta-analysis based on a literature search from databases PubMed, Web of Science, and Scopus, using keywords "SUDEP" or "sudden unexpected death in epilepsy" or "sudden unexplained death syndromes in epilepsy." Twenty-five publications met the inclusion and exclusion criteria and were enrolled in this study. RESULTS Body positions were documented in 253 cases of SUDEP. Of these patients, 73.3% (95% confidence interval [CI] = 65.7%, 80.9%) died in the prone position, whereas 26.7% (95% CI = 16.3%, 37.1%) died in nonprone positions. Binary random-effects analysis showed that prone position is significantly associated with SUDEP, as compared with nonprone position (p < 0.001). In addition, the prone position was reported in all 11 cases of video-EEG-monitored SUDEP. Moreover, in a subgroup of 88 cases of SUDEP in which demographics and circumstances of death were documented, the prone position was observed in 85.7% (95% CI = 74.6%, 93.3%) of patients aged 40 years or younger, but in only 60% (95% CI = 38.7%, 78.9%) of patients older than 40 years. Statistical analysis confirmed that the prone position was significantly more prevalent in the younger patient group, as compared with the older patient group (odds ratio 3.9; 95% CI = 1.4%, 11.4%; p = 0.009). CONCLUSION There is a significant association between prone position and SUDEP, which suggests that prone position is a major risk factor for SUDEP, particularly in patients aged 40 years and younger. As such, SUDEP may share mechanisms similar to sudden infant death syndrome.