Truck drivers who have obstructive sleep apnea and who do not attempt to adhere to a mandated treatment program have a much greater risk of a severe crash, according to a new study co-authored by Virginia Tech Transportation Institute researchers and featured in the March 21 online edition of the journal Sleep.

“Previous research has shown that obstructive sleep apnea is among the most common causes of excessive drowsiness or fatigue in the daytime, so this new analysis really underscores the risk truck drivers diagnosed with obstructive sleep apnea assume if they choose not to adhere to a treatment program,” said Erin Mabry, co-author of the research article and a senior research associate with the Virginia Tech Transportation Institute’s Center for Truck and Bus Safety.

More than 1,600 drivers diagnosed with obstructive sleep apnea were compared in the study to an equal number of drivers who were deemed unlikely to have obstructive sleep apnea. Drivers who fell in the former category were provided auto-adjusting positive airway pressure treatment, which was objectively monitored. The treatment program was implemented by trucking company Schneider National. Preventable, U.S. Department of Transportation-reportable crashes per 100,000 miles were compared across the study groups.

“What we found is that if we look at 1,000 truck drivers each working for a year, the drivers with obstructive sleep apnea who refuse treatment would have 70 preventable serious truck crashes, compared to 14 crashes experienced by both a control group and by drivers with sleep apnea who adhered to treatment,” says Stephen Burks, lead author of the research article and professor of economics and management at the University of Minnesota, Morris.

Drivers who did not follow the sleep apnea treatment administered by Schneider were discharged or quit during the program. The study observed that 60 percent of drivers who failed to accept the mandated sleep apnea treatment quit voluntarily before they could be discharged.

While Schneider removed drivers from its fleet who were non-compliant with the program, current federal regulations allow those drivers to keep their diagnosis of sleep apnea private, enabling them to work at another trucking firm.

“These results are important because, currently, drivers who are diagnosed with obstructive sleep apnea at a specific trucking firm with an internal mandated treatment program, and who choose not to accept treatment, can just quit and hire on with a firm that does not have such a program,” says Jeff Hickman, one of the study co-authors and a research scientist with the Center for Truck and Bus Safety at the Virginia Tech Transportation Institute. “Given the amount of job turnover in parts of the trucking industry, we can reasonably assume these drivers are going to drive for another firm. Essentially, as long as specific rigorous screening standards for obstructive sleep apnea are not in place, these drivers, if they remain untreated, are likely to remain a risk on the roadways.”

The researchers note that current federal regulations are the result of a previous lack of data available about the effectiveness of a mandated sleep apnea treatment program. However, the current study represents the first large-scale database available to determine how screening, diagnosing and monitoring obstructive sleep apnea among truck drivers can affect their crash risk.