Treating Sleep Apnea Reduces Risk Of Serious Motor Vehicle Crashes

Ontario, Canada - June 17, 2001

According to the United States Census Bureau, motor vehicle crashes are the leading cause of injury morbidity and mortality in the United States. There are approximately 6 million injuries and more than 40,000 deaths each year. It is estimated that sleep-related accidents comprise 15-20% of all motor vehicle crashes, resulting in thousands of serious injuries and death. Certainly not all sleep-related accidents are related to sleep disorders -- many are the result of simple sleep deprivation.

Studies have shown, however, that persons with untreated sleep apnea are more likely to have automobile accidents than persons without sleep apnea. Apnea patients who have been effectively treated have reported that they experience fewer accidents and improved driving. Researchers at the University of Western Ontario in London, Ontario, led by Charles F. P. George, M.D., decided to confirm these self-reports with an objective study. Their results were recently published in Thorax 2001; 56: 508-512.

These results confirm that treatment of patients with sleep apnea would reduce their risk of serious motor vehicle crashes to a rate similar to the general driving population.

For the study, 210 patients with obstructive sleep apnea (OSA) were treated with continuous positive airway pressure (CPAP) for at least 3 years. These patients had a mean age of 52, a body mass index of 35.5 and an apnea/hypopnea index of 54 events per hour. An equal number of randomly selected control drivers were also identified.

Using official driving records from the Ontario Ministry of Transportation, motor vehicle collision rates were then compared for 3 years before and after CPAP therapy for both patients and the control drivers.

Untreated patients with OSA had more motor vehicle collisions than controls. The rate of collisions per driver per year was .18 for the untreated patients, and .06 for the controls. The untreated apnea patients had three times the number of accidents as the controls.

Following CPAP treatment, the number of collisions per driver per year fell to normal (.06) while, in controls, the collision rate was unchanged over time. There were 27 patients who were not using CPAP following diagnosis. The collision rate in those untreated patients remained high over time.

The authors conclude that patients with untreated sleep apnea have increased motor vehicle crashes, but this rate decreases to normal once patients are treated with CPAP.

The authors also note that "not all patients with sleep apnea actually have collisions. In this study more than half of the patients never had any collisions either before or after treatment."

Such results should be of great value to practicing physicians who must make assessments about ability to drive as any restrictions on driving because of OSA could be safely removed after treatment, they add.

In an editorial published in the same issue of Thorax, Drs. L. J. Findley and Paul M. Suratt discuss the economic consequences of the findings. They estimate that treating 500 patients in the US for 3 years would likely prevent 180 serious crashes, with 36 serious injuries. The costs of those 180 accidents were estimated to be $369,000 in direct property damage and medical expenses and some $648,000 in lost wages, legal expenses, and administrative costs of both government and insurance companies. That's a total economic savings of over $1 million dollars for each 500 treated patients.

It is generally estimated that over 80-90% of sleep apnea patients remain undiagnosed and untreated, with the number of untreated patients in the 12-15 million range.

Suratt and Findley conclude that "Preventing serious motor vehicle crashes by treating sleep apnea is beneficial to everyone. For drivers with sleep apnea and those they injure, it avoids injury and death and loss of wages and property. For insurance companies and employers it eliminates the economic consequences of these problems. Unfortunately, some government agencies and insurance companies have arbitrary and shortsighted policies which limit treatment for people with sleep apnea. These obstacles, like dangerous objects on a highway, may contribute to serious and costly motor vehicle crashes."