4. Fatal overdoses in a cohort of chronic pain patients

Chronic pain patients may be at an increased risk of drug overdoses due to comorbid psychiatric disorders and heightened access to prescription drugs such as opioids. We aimed to describe persons who died of an overdose in a cohort of chronic pain patients.

Utilizing nationwide healthcare registers, we identified persons with filled prescriptions reimbursed for chronic pain in Norway in 2010-2019 (N=569,047). For these persons, we extracted data on causes of death and filled prescriptions in 2010-2019, and primary and secondary healthcare diagnoses in 2008-2019. Overdoses were identified with the European Monitoring Centre for Drugs and Drug Addiction definition.

Overall, 624 (0.11%) persons died of an overdose in 2010-2019. They were on average 48.5 years old and 57.4% were men. Most, 66.7%, had overdosed non-intentionally and 61.9% due to pharmaceutical opioids, excluding methadone. In the last three months, 63.8% had been dispensed opioids and 68.7% benzodiazepines or benzodiazepine-related drugs. Compared to the others in the cohort, individuals who had died from an overdose had more frequently diagnosed depression (67.9% vs. 31.8%), anxiety (60.1% vs. 21.6%), any substance use disorders, including alcohol use disorder (76.3% vs. 18.0%), previous suicide attempts (21.2% vs. 2.2%), and non-fatal poisonings with pharmaceuticals (35.6% vs. 3.1%).

Among persons with chronic pain, overdose deaths were connected to substantial psychiatric morbidity and frequent prescription drug use prior to death. High proportions of non-intentional overdoses and of pharmaceutical opioids as the cause can be considered alarming for prescribers and other healthcare professionals.