Comparative out-of-hospital mortality of long-acting opioids prescribed for non-cancer pain: A retrospective cohort study

Abstract

Purpose: Despite significant growth of opioid prescriptions, only limited data are available regarding the comparative safety of long-acting opioids for chronic non-cancer pain. Recent data suggest that transdermal fentanyl and oxycodone CR may have greater toxicity than morphine SR in patients with non-cancer pain. Thus, we compared the risk of out-of-hospital deaths in patients with non-cancer pain filling prescriptions for transdermal fentanyl or oxycodone CR with that for morphine SR. Methods: We conducted a retrospective cohort study in 50 658 patients enrolled in Tennessee Medicaid who filled prescriptions for transdermal fentanyl (n = 8717), oxycodone CR (n = 14 118), or morphine SR (n = 27 823) between 1999 and 2011. We excluded individuals with cancer or other life-threatening diagnoses and used propensity scores to adjust for multiple potential confounders. The primary outcome was out-of-hospital mortality. Results: During 44 385 person-years of follow-up, 689 patients died. The out-of-hospital mortality rate among all study subjects was 155/10 000 patient-years. Contrary to earlier data suggesting greater risk, mortality was not significantly different in patients filling prescriptions for transdermal fentanyl compared with morphine SR (adjusted HR = 0.96, 95% C.I.: 0.77-1.21); moreover, patients filling prescriptions for oxycodone CR had lower mortality risk compared with those filling prescriptions for morphine SR (adjusted HR = 0.79, 95% C.I. 0.66-0.95). Conclusion: In the study population, long-acting opioids for non-cancer pain were associated with high out-of-hospital mortality rates. We found comparable out-of-hospital mortality risks associated with transdermal fentanyl and morphine SR. The risk of out-of-hospital death for oxycodone CR was lower than that for morphine SR.