Motor Vehicle Accidents in Patients with Excessive Daytime Sleepiness

Excessive daytime sleepiness (EDS) is a common problem in patients referred to sleep clinics, which could result in adverse consequences in their personal and social activities including motor vehicle accidents (MVAs). Epworth Sleepiness Scale (ESS) and Multiple Sleep Latency Test (MSLT) are known methods for measuring EDS. In this study, we aimed to evaluate the relationship between EDS and MVAs. Medical records of 144 patients (106 men) with EDS referred to Baharloo Sleep Clinic, Tehran, Iran, were assessed in this cross-sectional study. All participants filled out a questionnaire including demographic characteristics, ESS, and history of MVAs due to sleepiness in the last five years and underwent full-night polysomnography (PSG) and MSLT. Sleepiness was categorized to normal, moderate, or severe according to mean sleep latency (MSL) in MSLT. Patients with history of MVAs had a significantly less MSL and higher ESS scores than those without MVAs (6.6 ± 3.9 vs. 9.3 ± 6.5, P = 0.038; and 17.9 ± 4.4 vs. 15.6 ± 5.5, P = 0.030, respectively). MVAs were reported in 41.9%, 31.0%, and 16.1% of patients with severe, moderate, and normal sleepiness, respectively. There was a significant relationship between severity of sleepiness and history of MVAs (P = 0.020). Regression analysis showed that after adjustment for age and sex, ESS and MSL remained significantly different between patients with and without MVAs. ESS score and MSL would help sleep clinicians to find high-risk patients for safety-sensitive jobs, the issue which should not be overlooked by them during visits in sleep clinic.