OOIDA questions objectivity of latest sleep study

By Mark Schremmer, Land Line staff writer | 3/24/2016

A study claiming truck drivers with untreated sleep apnea are much more likely to crash was released by the University of Minnesota Morris and others on Monday, March 21. The Owner-Operator Independent Drivers Association fired back at the study on Thursday.

The study’s findings were released less than two weeks after the Federal Motor Carrier Safety Administration and Federal Railroad Administration published an advanced notice of public rulemaking regarding the possibility of requiring commercial drivers and railroad workers to undergo evaluation and treatment for sleep apnea.

“To put our findings in context, if we look at 1,000 truck drivers each working for a year, the drivers with obstructive sleep apnea who refuse mandated 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,” said Stephen Burks, lead author of the study and professor of economics and management at Minnesota Morris.

The retrospective study compares more than 1,600 Schneider National truck drivers diagnosed with obstructive sleep apnea to an equal number of drivers screened as unlikely to have the condition, according to a news release from Minnesota Morris. Drivers with sleep apnea were given an auto-adjusting positive airway pressure machine, and its use was electronically monitored. The rates of preventable serious truck crashes per 100,000 miles driven were compared across the study groups. The study looked at drivers diagnosed with sleep apnea who adhered to treatment and those who were non-adherent.

OOIDA points to some potential conflicts of interest in the study involving several of the contributors of the study. Burks has worked with Schneider on studies for the past 11 years, according to OOIDA. Schneider has long advocated for sleep apnea testing. Mark Berger is the president of Precision Pulmonary Diagnostics, which has received fees for providing sleep apnea-related services to Schneider, OOIDA said. Charles Czeisler has received consulting fees from or has served as a paid member of scientific boards for Phillips Electronics, received royalties from Phillips Respironics, and had education and research support from many pharmaceutical companies that manufacture and sell sleep aids.

“From the standpoint of objectivity or scientific analysis, this is still somebody’s opinion and largely the opinion of people who have an economic interest in expanding sleep disorder testing,” OOIDA Executive Vice President Todd Spencer said. “If you’re going to take anything away from this effort at all, it’s going to be toward Schneider – nobody else. It was on their drivers in their system and all of the controls based on decisions made by them. It wasn’t illuminating in any way as far as extrapolating any kind of legitimate safety conclusions.”

The web-supplement to the research reveals some of the study’s limitations.

“However, if the No Adherence drivers have a higher crash risk than their controls (as is reported in the main text, section 3), it is not possible to conclude that this difference was caused by the effect of untreated obstructive sleep apnea,” the web-supplement said. “A higher crash rate for the No Adherence drivers is consistent with there being such an effect. But other factors affecting crash risk may also vary in a non-random manner between the No Adherence drivers and other drivers, since these groups are self-selected.”

Among OOIDA’s complaints about the effectiveness of the study was that Schneider was the only carrier used for the research.

OOIDA noted:

  • Schneider already has a health and safety program in place that pays for sleep apnea testing.
  • Schneider is one of the largest freight carriers in the United States.
  • The study team and the analysis are constrained by the fact that all research participants were employed by one carrier and may or may not reflect the general truck driver population.
  • Extrapolating findings to the general population from a single large carrier is not appropriate;
  • The groupings within the population were not randomized. The study’s authors noted “the primary limitation of the study is the fact that under a mandated treatment regimen, the division into treatment adherence groups after a positive diagnosis was, of necessity, self-selected and not randomly assigned.”
  • There may be a significant issue with data from the employer’s obstructive sleep apnea program in that drivers were only diagnosed after attaining sufficient tenure. Thus, safety selection, due to discharge of drivers who accumulated unacceptable preventable crash histories early in their tenure, prevented many of those with relevant crashes from ever being screened or diagnosed for obstructive sleep apnea.

“This brings up the next point that the number of diagnosed non-adherent drivers was reduced during the research by being terminated or quitting before the end of the research,” OOIDA Foundation Researcher Andrew King said. “This would affect the outcome when looking at percentages. The smaller the number of non-adherent drivers, the smaller the number of crashes needed to show a percentage increase but that’s not really reflective of the overall group. In fact, only 17.2 percent of non-adherent drivers were still employed by the end of the study period.”

OOIDA also points out that the study itself says while “increased crash risk for drivers who do not comply with mandatory treatment may be due to the effects of untreated obstructive sleep apnea, the present study cannot determine the relative contributions of untreated obstructive sleep apnea versus factors, such as a more general disregard of safety rules that leads to both non-adherence and unsafe driving habits.”

OOIDA said the authors failed to mention the limitations of the study in their public statement.

Another area of contention by OOIDA in regards to mandatory testing of sleep apnea for those with large necks or a high body mass index is that the Association believes it is an unfair and unnecessary cost to the driver.

“One very interesting finding was that those who had the physical characteristics of someone who had sleep apnea but tested negative did not have higher crash rates than the control groups,” King said. “But if it hadn’t been paid for by Schneider, they sure would be out a lot more money than the others.”

“We have yet to see any legitimate verifiable data that didn’t come from someone with an economic interest in expanding the discussion that indicates this is a legitimate safety issue,” Spencer said. “The extent that they go to in order to imply that there’s something to it is kind of mind-boggling. In this instance, they didn’t even look at fault accidents, but they looked at what they perceived to be preventable accidents. A truck driver certainly can be involved in lots of ‘preventable’ accidents where they didn’t do anything wrong.”

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