Prolonged opioid use among opioid-naive individuals after prescription for nonspecific low back pain in the emergency department

Low back pain is a leading cause of disability globally. It is a common reason for presentation to the emergency department where opioids are commonly prescribed. This is a retrospective cohort study of opioid-naive adults with low back pain presenting to 1 of 4 emergency departments in Nova Scotia. We use routinely collected administrative clinical and drug-use data (July 2010-November 2017) to investigate the prevalence of prolonged opioid use and associated individual and prescription characteristics. In total, 23,559 eligible individuals presented with nonspecific low back pain, with 84.4% being opioid-naive. Our study population included 4023 opioid-naive individuals who filled a new opioid prescription within 7 days after their index emergency department visit (24.4%). The prevalence of prolonged opioid use after a new opioid prescription for low back pain (filling an opioid prescription 8-90 days after the emergency department visit and filling a subsequent prescription +/- 30 days of 6 months) was 4.6% (185 individuals). Older age and female sex were associated with clinically important increased odds of prolonged opioid use. First prescription average >90 morphine milligram equivalents/day (odds ratio 1.6, 95% confidence interval 1.0-2.6) and greater than 7-day supply (1.9, 1.1-3.1) were associated with prolonged opioid use in adjusted models. We found evidence of declining opioid prescriptions over the study period, but that 24.3% of first opioid prescriptions in 2016 would not have aligned with current guideline recommendations. Our study provides evidence to support a cautious approach to prescribing in opioid-naive populations.

Automated summary

Low back pain is a common reason for emergency department visits where opioids are often prescribed. This study found that older age and female sex were associated with increased odds of prolonged opioid use among opioid-naive adults with low back pain. Higher initial prescription doses and longer supply durations were also linked to prolonged opioid use. The study suggests a cautious approach to prescribing opioids for opioid-naive populations.