People with obstructive sleep apnea have a markedly increased risk of severe motor vehicle crashes involving personal injury, according to a study presented at the American Thoracic Society 2007 International Conference, on Sunday, May 20.

The study of 800 people with sleep apnea and 800 without the nighttime breathing disorder found that patients with sleep apnea were twice as likely as people without sleep apnea to have a car crash, and three to five times as likely to have a serious crash involving personal injury. Overall, the sleep apnea group had a total of 250 crashes over three years, compared with 123 crashes in the group without sleep apnea.

While many previous studies have shown that sleep apnea patients are at increased risk of car crashes, this study is the first to look at the severity of those crashes. “We were surprised not only about how many of the sleep apnea patients’ crashes involved personal injury, but that some patients had fairly mild sleep apnea and were still having serious crashes,” says Alan Mulgrew, M.D., of the UBC Sleep Disorders Program in Vancouver, British
Columbia.

Source: American Thoracic Society
Patients’ self-reported feeling of sleepiness was not found to be linked with an increased risk of car crashes, suggesting that patients are unaware of their driving hazard, Dr. Mulgrew says. Even patients with fairly mild sleep apnea were at increased risk of car crashes. “Based on these findings, I now consider driving risk when deciding on treatment for patients with mild sleep apnea,” he says.

The study is the biggest one to combine validated sleep apnea diagnosis through an overnight sleep study called polysomnography, with data from insurance records to verify motor vehicle crashes and their severity.

In obstructive sleep apnea, the upper airway narrows, or collapses, during sleep. Periods of apnea end with a brief partial arousal that may disrupt sleep hundreds of times a night. Obesity is a major risk factor for sleep apnea.

The study found that while in the general population men have more vehicle crashes than women, among sleep apnea patients, men and women crash at a similar rate.

Although the issue of treatment is not addressed by this study, Dr. Mulgrew notes that data from other groups suggests that crashes related to sleep apnea are preventable.

“Severity of Motor Vehicle Crashes in Obstructive Sleep Apnea Patients”(Session A30; Abstract # 1227; Poster Board # E2)