Excessive daytime sleepiness increases the risk of motor vehicle crash in obstructive sleep apnea

Abstract

Study objectives: (1) To describe the incidence rate of motor vehicle crashes (MVCs) in patients with obstructive sleep apnea (OSA); and (2) to investigate MVC risk factors in OSA patients.

Methods: A retrospective case-series observational study was conducted using data from the West Australian Sleep Health Study at a tertiary hospital-based sleep clinic. Participants were patients (N = 2,673) referred for assessment of suspected sleep disordered breathing. Questionnaire data were collected including age, sex, years of driving, near-misses and MVCs, sleepiness, and consumption of alcohol and caffeinated drinks. Overnight laboratory-based polysomnography was performed using standard methodology.(1) Poisson univariate and negative binomial multivariable regression models were used to investigate associations between risk factors and MVC and near-miss risk in patients with untreated OSA.

Results: In patients with untreated OSA, the crash rate was 0.06 MVC/person-year compared with the general community crash rate of 0.02 MVC/person-year. The rate ratio comparing very sleepy men with normal men was 4.68 (95% CI 3.07, 7.14) for near-misses and 1.27 (95% CI 1.00, 1.61) for crashes, after adjusting for confounders. In women there was a significant association with sleepiness score (p = 0.02) but no dose effect across quartiles.

Conclusions: Untreated OSA is associated with an increased risk of near-misses in men and women and an increased risk of MVCs in very sleepy men. There is a strong association between excessive daytime sleepiness and increased report of near-misses. Our data support the observation that it is those patients with increased sleepiness regardless of OSA severity who are most at risk.

Keywords: Motor vehicle crashes; gender; near-misses; obstructive sleep apnea; severity; sleepiness.

Figure 1. Near-miss rate and severity of OSA for men and women

Error bars represent 95% CI. Asterisks represent a significant difference between men and women where p < 0.001. See Table 3 for number of subjects in each group.

Figure 2. Near-miss rate and subjective sleepiness for men and women

Error bars represent 95% CI. Asterisks represent a significant difference between men and women where p < 0.001. See Table 3 for number of subjects in each group.

Figure 3. Crash rate and severity of OSA for men and women

Error bars represent 95% CI. Asterisks represent a significant difference between men and women where p < 0.001. See Table 3 for number of subjects in each group.

Figure 4. Crash rate and subjective sleepiness for men and women

Error bars represent 95% CI. Asterisks represent a significant difference between men and women where p < 0.001. See Table 3 for number of subjects in each group.