No Clear Opioid Dose Threshold for Opioid Overdose Death Risk
Higher-dose opioid therapy for chronic pain is associated with opioid overdose, but prescribing guidelines that recommend dosing limits are based on sparse data and arbitrary dosing categorizations. Researchers used a nested case-control methodology with Veterans Administration and National Death Index data to examine the association of prescribed opioid dosage as a continuous measure in relation to risk of unintentional opioid overdose death to determine a threshold for opioid prescribing limits.
- Among 399 patients prescribed opioid therapy and who died of overdose, 221 opioid overdose death cases were compared with 221 controls matched with cases on age, sex, race/ethnicity, prescribing date range, mental health and substance use diagnosis, medical co-morbidity, and benzodiazepine prescription.
- The average prescribed daily opioid dosage was 98.1 morphine-equivalent mg (MEM) for opioid overdose death cases and 47.7 MEM for controls.
- In a receiver operating characteristic (ROC) analysis, “dosage was a moderately good ‘predictor’ of opioid overdose death,” but almost 30% of cases were prescribed ≤ 30 MEM.
- A dose threshold below the 100 MEM would potentially protect 31% of cases and affect 11% of controls, while a dose threshold of 50 MEM would potentially protect 66% of cases and affect 29% of controls.
Comments:
This study confirms the relationship between prescribed opioid dose and the risk of opioid overdose death, but was not able to discern a clear dose threshold distinguishing overdose cases from controls. Perhaps because opioid overdose deaths frequently involve multiple substances, there is no prescribed dose threshold that eliminates overdose risk or can be used to guide prescribing policy on dose limits.
Joseph Merrill, MD, MPH
Reference:
Bohnert AS, Logan JE, Ganoczy D, Dowell D. A detailed exploration into the association of prescribed opioid dosage and overdose deaths among patients with chronic pain. Med Care. 2016;54(5):435–441.