Severe pain, not pressure to return to work or lack of accommodation offer, linked to opioid use post-injury

Previous studies have shown that opioids are commonly prescribed after work-related injuries, which may lead to opioid harms. However, it is unclear whether challenges experienced by workers during the return-to-work experience contribute to opioid use. This study set out to examine the association between two plausible return-to-work factors and opioid use by injured workers. One factor was whether the injured worker felt they returned to work too early. The other was whether workplace accommodations were offered to the injured worker.

To conduct this study, the research team drew on data from two surveys, conducted in 2019 and 2021 as part of the Ontario Life After Work Injury Study (OLAWIS). This is an IWH-led research project examining the health and labour market outcomes of Ontario workers after they’ve experienced a work-related injury or illness. The 1,793 participants in this study were at least 18 years old and had a work-related injury or illness that led to an accepted lost-time compensation claim with the provincial workers’ compensation system—i.e., the Workplace Safety & Insurance Board (WSIB).

Participants were interviewed 18 months after the injury or illness. They were asked about their use of codeine, oxycodone or other opioid products over the previous 12 months. To assess pain, participants were asked how much pain they experienced at the time of the interview, and how much pain interfered with their normal work in and out of the home in the previous four weeks. They were also asked two questions related to their return to work: (1) Do you feel you went back to work too soon, too long, or just the right time after the injury? and (2) In the time following your injury, did your workplace offer you modified or alternative duties in order to help you get back to work?

Compared to workers who felt they did not return to work too soon and had no or only mild pain, the odds of opioid use were higher among those who had severe pain. These odds were higher both for workers who felt they returned to work too soon (2.9 times higher) and those who did not feel they returned to work too soon (3.0 times higher).

Similarly, compared to those who had an offer of accommodation and had no or mild pain, workers with severe pain had increased odds of opioid use. These odds were higher both for workers with an accommodation offer (2.8 times higher) and those without (2.7 times higher).

The above findings have already taken into account differences in a wide range of factors, including whether the workers were in jobs that were hazardous or physically demanding.

The findings of this exploratory study do not support the premise that return-to-work timing (i.e., the workers’ perception that they returned to work too soon) and the lack of workplace accommodations are associated with opioid use in the aftermath of a work-related injury or illness. The presence of severe pain appears to be the main factor associated with opioid use. This finding suggests the need for effective alternatives for pain management in the injured worker population.

This is one of only a few studies to date to explore the link between specific factors in the return-to-work process and the use of opioids among injured workers. A strength of this study was its large sample. A weakness of the study was the cross-sectional (“moment in time”) design, which does not permit the research team to determine the order of events post-injury. For example, study participants were asked about their opioid use in the previous 12 months, but their experience of pain was assessed over the previous four weeks. As a result of this missing data on how much pain participants experienced earlier in the post-injury period and on when opioids were initiated, the team could not be confident that the pain level reported at 18 months is the same as the pain level preceding the opioid use. Similarly, without data on the timing of the return-to-work and accommodation offers in relation to pain and opioid use, the team could not determine whether opioid use preceded or followed the return-to-work or accommodation offers. Also missing from the data were information on whether opioids were used for the compensated work injury or other reasons or on whether the offered accommodation was adequate.

As a result of these limitations, the findings of this study should be considered preliminary. Further research using a longitudinal design is needed on the role of pain and return-to-work factors on the use of opioids by workers after a work-related injury or illness.