Factors associated with injury in REM sleep behavior disorder

Objective: As factors associated with injury in rapid eye movement (REM) sleep behavior disorder (RBD) remain largely unknown, we aimed to identify such factors. Methods: We surveyed consecutive idiopathic (iRBD) or symptomatic RBD patients seen between 2008 and 2010 regarding RBD-related injuries. Associations between injuries and clinical variables were determined with odds ratios (OR) and multiple logistic regression analyses. The primary outcome variables were injury and injury severity. Results: Fifty-three patients (40%) responded. Median age was 69 years, and 35 (73.5%) were men. Twenty-eight (55%) had iRBD. Twenty-nine (55%) reported injury, with 37.8% to self and 16.7% to the bed partner. 11.3% had marked injuries requiring medical intervention or hospitalization, including two (4%) subdural hematomas. iRBD diagnosis (OR = 6.8, p = 0.016) and dream recall (OR = 7.5, p = 0.03) were associated with injury; and iRBD diagnosis was independently associated with injury and injury severity adjusting for age, gender, DEB frequency, and duration. Falls (p = 0.03) were also associated with injury severity. DEB frequency was not associated with injury, injury severity, or falls. Conclusions: Injuries appear to be a frequent complication of RBD, although the relatively low response rate in our survey could have biased results. iRBD patients are more likely to suffer injury - and more severe injuries - than symptomatic RBD patients. In addition, recall of dreams was also associated with injury, and dream enactment behavior (DEB)-related falls were associated with more severe injuries. One in nine patients suffered injury requiring medical intervention. The frequency of DEB did not predict RBD-related injuries, highlighting the importance of timely initiation of treatment for RBD in patients having even rare DEB episodes. Future prospective studies will be necessary to define predictors of injury in RBD.