Link found between prescription drug use before, after injury

Workers taking opioids or benzodiazepines (anxiety medications) prior to a work-related injury were more likely than other workers to continue taking the drugs after the injury, according to a National Institute for Occupational Safety and Health (NIOSH)-funded study at the University of Washington in Seattle. In addition, these workers were also more likely to receive workers’ compensation, reports the study in the Journal of Occupational and Environmental Medicine.

To better respond to the nationwide opioid epidemic, NIOSH supports research on work-related factors on the use of these drugs. In one of the first large studies of pre-and post-injury use of opioids and benzodiazepines, researchers wanted to understand whether taking either drug before a work-related injury affected later use. They also aimed to find if pre-injury use affected the likelihood of receiving workers’ compensation.

Researchers looked at 313,543 workers’ compensation claims, with dates of injury between January 2012 and December 2015, from the Washington State Department of Labor and Industries. Most of the claimants (67.1%) were male with an average age of 39 years. Researchers also reviewed records from the Washington State Prescription Monitoring Program for opioids and benzodiazepines.

Researchers then used statistical methods to compare post-injury drug use to three types of pre-injury drug use based on workers’ medical prescriptions: 1) chronic—prescription for 60 or more days in the 90 days before injury; 2) intermittent—prescription for fewer than 60 days in the 90 days before injury, and prescription in the 91–180 days before injury; and 3) acute—prescription for fewer than 60 days in the 90 days before injury.

They learned that in the 90 days before the injury occurred, opioids were more commonly used than benzodiazepines among the workers in the study. Workers who took either one of the drugs were more likely to receive workers’ compensation and to continue taking the drugs after a work-related injury. The use of either drug before injury was associated with a greater likelihood of use after injury, although the greatest risk occurred among workers with chronic use, as shown below.

Table 1. Opioid and Benzodiazepine Use Before and After Work-related Injury (rounded numbers)
Pre-injury Use	Post-injury Use, Opioids	Post-injury Use, Benzodiazepines
None	23%	2%
Chronic	98%	95%
Intermittent	71%	57%
Acute	51%	36%

The design of this study only shows a relationship, not cause and effect, between pre- and post-injury use of opioids and benzodiazepines. Nevertheless, the study’s findings indicate that the risk for long-term disability after a work-related injury may be greater among workers already taking opioids or benzodiazepines than among those who do not take them. More research is necessary to understand the extent of this relationship.