Workers Compensation
Two in three injured workers prescribed opioids after a back or neck injury show high-risk opioid prescribing within 90 days. That early pattern doubles the odds the opioids are still there a year later.
A 2025 Monash University study published in CNS Drugs followed 6,278 injured workers with accepted workers' compensation claims for back and neck conditions who filled an opioid prescription in the first 90 days after injury. Drawing on a decade of WorkSafe Victoria claims data from 2010 to 2019, it is one of the clearest looks yet at how opioids in workers compensation claims start, and how often an early prescription becomes a long-term one. For injury managers, the message is uncomfortable but useful: the file usually tells you within 3 months which claims are heading for trouble.
What counts as high-risk opioid prescribing?
The researchers assessed each worker's opioid dispensing in the first 90 days against four indicators drawn from Australian and US prescribing guidance. Meeting any one of them classified the prescribing as high risk.
| Indicator | What it looks like on a file | Share of workers affected |
|---|---|---|
| Concurrent psychotropic prescribing | An opioid overlapping with another psychotropic medicine such as pregabalin, a benzodiazepine, an antidepressant or an antipsychotic, for at least 1 day within a 30-day period | 45.2% |
| Early long-acting opioids | Extended-release or long half-life opioids, such as modified-release oxycodone, fentanyl or tapentadol, supplied early despite guidelines recommending only short-acting opioids for acute injury pain | 38.0% |
| High first-dispense volume | More than 350 mg oral morphine equivalent supplied on the first dispensing occasion, roughly more than 50 mg per day for the first week | 30.0% |
| High average daily dose | An average of more than 50 mg oral morphine equivalent per day across the first 90 days | 7.3% |
Overall, 67.1% of workers met at least one indicator. The most common was not a big dose. It was combination risk: an opioid sitting alongside another sedating medicine, a pattern the authors link to the well-documented growth in pregabalin prescribing on injured worker files.
How common is persistent opioid use after a back or neck injury?
The study tracked opioid dispensing for a further 9 months after the 90-day window and grouped workers by trajectory. By that measure, 22.8% of workers who received opioids early were persistent opioid users at 1 year. For comparison, the authors note that estimates of persistent opioid use over 1 year in the general Australian population without cancer sit at a small fraction of that figure.
Persistence was not evenly spread. On back and neck injury claims, three factors stood out after adjustment:
- Workers who had not returned to work at 3 months were nearly eight times more likely to be persistent opioid users at 12 months. This was the strongest predictor in the study.
- Workers with any early high-risk prescribing indicator had roughly double the odds of persistent use.
- Workers living in the most disadvantaged areas had modestly higher odds, while those in the most advantaged areas had lower odds.
Why do the first 90 days matter so much?
Because the two strongest signals in the study are both visible inside that window. Work status at 3 months is already on the certificate of capacity. The prescribing pattern is already in the pharmacy data: the size of the first dispense, the formulation chosen, and what else is on the medication list. Neither requires waiting for the claim to mature.
The core finding: early high-risk opioid prescribing doubled the odds of persistent opioid use at 1 year (adjusted odds ratio 2.19). The pattern that predicts a 12-month opioid claim is usually established, and detectable, within the first 90 days.
The authors also found that high-risk prescribing became more common in claims received from 2015 to 2019 compared with 2010, driven largely by the growing overlap of opioids with other psychotropics. Notably, most of the study period predates Victoria's mandatory real-time prescription monitoring program, which began operating in 2019, so the early-warning burden in that era sat almost entirely with the people reading the file.
Which claims deserve a closer look?
The study points injury managers toward a specific set of files rather than a general anxiety about opioids:
- Regional and remote workers. Workers outside major cities had higher odds of early high-risk prescribing, consistent with thinner access to pain management alternatives.
- Combination scripts. An opioid plus pregabalin, a benzodiazepine or another sedating medicine was the single most common risk pattern, and it is the one most associated with overdose harm in the wider literature.
- Long-acting opioids appearing early. Guidelines reserve these for continuous, severe or chronic pain, yet 38% of workers received them in the acute phase.
- No return to work at the 3-month mark. Whatever the injury, continued work incapacity at 3 months should prompt a medication question, not just a rehabilitation one.
What can injury managers do inside the window?
None of this asks a claims professional to second-guess a prescriber. It asks them to notice patterns the data says are predictive, and to bring clinical eyes to the file early.
- Read the first pharmacy account line, not just the total. A large first dispense or a modified-release formulation in week one is a flag the study validates.
- Scan the medication list for overlap. Opioid plus pregabalin or a benzodiazepine was the most common high-risk pattern on these claims.
- Treat "not back at work at 3 months" as a medication trigger. It was the strongest predictor of persistent opioid use in the study.
- Request an independent medication review while the pattern is still forming. A pharmacist review in the first 90 days can document interaction risks, test whether long-acting opioids are clinically justified, and give the treating GP specific, actionable recommendations before use becomes entrenched.
Key Takeaways
- Two in three injured workers prescribed opioids after back and neck injuries met at least one high-risk prescribing indicator in the first 90 days.
- Early high-risk prescribing roughly doubled the odds of persistent opioid use at 1 year.
- A worker not back at work at 3 months was nearly eight times more likely to still be using opioids at 12 months.
- Concurrent prescribing of opioids with other psychotropics, such as pregabalin and benzodiazepines, was the most common risk pattern, ahead of long-acting opioids and large first dispenses.
- The practical window to change the trajectory is the first 90 days, when the pattern is visible but not yet entrenched.
Frequently Asked Questions
What counts as high-risk opioid prescribing on a claim?
The study used four indicators: more than 350 mg oral morphine equivalent on the first dispensing occasion, an average daily dose above 50 mg over the first 90 days, early supply of long-acting opioids, and an opioid overlapping with another psychotropic medicine such as pregabalin, a benzodiazepine, or an antidepressant.
Does early high-risk prescribing predict long-term opioid use?
Yes. Workers with any high-risk indicator in the first 90 days had roughly double the odds of persistent opioid use at 1 year, after adjusting for age, sex, injury and other factors.
Which injured workers are most likely to become persistent opioid users?
Workers who had not returned to work at 3 months were nearly eight times more likely to be using opioids at 12 months. Workers in the most disadvantaged areas and those with early high-risk prescribing also had higher odds.
When should an injury manager request a medication review?
Inside the first 90 days, as soon as a high-risk indicator appears on the file. A review requested after opioid use is entrenched is working against a pattern that has already set.
Primary source: Tefera et al., Early High-Risk Opioid Prescribing and Persistent Opioid Use in Australian Workers with Workers' Compensation Claims for Back and Neck Musculoskeletal Disorders or Injuries, CNS Drugs, 2025, analysing WorkSafe Victoria claims data.
