Lower-back work injury claimants treated with opioids stay off work longer, study finds

An analysis by McMaster researchers has found that workers disabled by low back pain and receiving disability benefits are more likely to stay on claim if they are treated with opioids.

This study of administrative data from the Ontario Workplace Safety and Insurance Board (WSIB) was published by BMJ Open today.

"Our findings that reimbursement for early opioids is associated with longer claim duration is worrisome," said Jason Busse, lead author, an assistant professor of anesthesia and researcher with the Michael G. DeGroote Institute for Pain Research and Care at the Michael G. DeGroote School of Medicine.

The research team conducted an observational cohort study, analyzing 1,442 claims for acute, uncomplicated lower back pain approved by the Ontario WSIB in 2005 that remained on full benefits at four weeks after claim approval.

"The evidence does not establish causation," Busse added. "For instance, although we enrolled workers with similar injuries, those who received opioids may have been worse off – that is why they received opioids – and that may be the reason for delay in claim resolution. On the other hand, adverse effects of opioids on mental and physical function could be the reason. Definitive research studies – ideally randomized trials – need to sort this out."

"Our findings come at a time of crisis for WSIB," Busse noted. "To manage their growing unfunded liability, which was $13 billion in 2013, the Ontario WSIB has increased their claim denial rate, decreased benefits to injured workers, reduced WSIB staff, and raised employer premiums. These approaches do not address optimal management of disabled workers."