Mortality risk from opioid overdose previously has been measured in terms of thresholds of risk. Four scientists linked to the UNC Gillings School of Global Public Health are co-authors on a new cohort study finding that dose-dependent opioid overdose risk among patients does not show evidence of a distinct risk threshold.
Co-authors are Dr. Nabarun Dasgupta, 2013 epidemiology alumnus; Dr. Steve Marshall, professor, and Dr. Michele Jonsson-Funk, research assistant professor, members of the epidemiology faculty; and Dr. Kurt Ribisl, professor of health behavior and member of the UNC Lineberger Comprehensive Cancer Center.
Their article, “Cohort Study of the Impact of High-dose Opioid Analgesics on Overdose Mortality,” was published online September 1 by Pain Medicine.
The researchers used Poisson regression models to quantify dose-dependent overdose mortality across a large spectrum of clinically common doses and examined the contributions of benzodiazepines and extended-release opioid formulations to mortality.
Using one year of name-linked mortality data from a controlled substances prescription-monitoring program in North Carolina, the team discerned that opioid analgesics were dispensed to 22.8 percent of North Carolina residents. There were 629 overdose deaths during the study year, half of which had an opioid analgesic prescription active on the day of death.
The models found that mortality rates increased gradually as the average daily milligrams of morphine equivalents rose.
Additionally, 80 percent of opioid analgesic patients also received benzodiazepines, and rates of overdose death were 10 times higher among those co-dispensed both opioid analgesics and benzodiazepines.
This cohort study underscores the urgent need to disseminate updated guidance to the medical community about the risk associated with co-prescribing classes of medicines. This will facilitate a better balance between pain relief and overdose risk for patients using opioids.