Continued opioid use following an emergency department presentation for low back pain

Objective: To investigate the proportion of patients with low back pain who receive an opioid analgesic prescription on hospital discharge, the proportion using opioid analgesics 4 weeks after discharge, and to identify predictors of continued opioid analgesic use at 4 weeks after an ED presentation in opioid-naïve patients.

Methods: An observational cohort study nested within a randomised controlled trial in four EDs in New South Wales, Australia. Participants were adults who presented to the ED with non-specific low back pain or low back pain with lower limb neurological signs and symptoms. Electronic medical records supplemented the patient-reported pain and use of opioid analgesics at 4-week follow up.

Results: Of the 104 patients included, 33 (31.7%, 95% confidence interval [CI] 22.9-41.6) received an opioid analgesic prescription at hospital discharge and 38 (36.5%, 95% CI 27.3-46.6) reported taking an opioid analgesic for pain 4 weeks after the ED presentation. Among opioid-naïve patients (n = 85), older age (odds ratio [OR] 1.04, 95% CI 1.00-1.08, P = 0.031) was the only predictor for continued opioid analgesic use at 4 weeks post-ED presentation.

Conclusion: About one-third of patients who present to the ED with low back pain receive an opioid analgesic prescription on discharge and are taking an opioid analgesic 4 weeks later. These findings justify future research to identify strategies to reduce the risk of long-term opioid use in patients who present to the ED with low back pain.