The rate of mortality attributable to drug poisoning has risen consistently since the 1990s. State-based vital statistics registries estimate the incidence of drug overdose deaths using International Classification of Disease 10th revision (ICD-10) codes. Composite ICD-10-based definitions of “overdose” may include deaths that do not involve controlled substances while missing deaths that do. This has implications for incidence estimates, funding priorities, and intervention evaluation.
The study finds that approximately 1.5 percent of all deaths among NC residents were due to overdose. Prescription opioids were involved in 63.4 percent of drug overdose deaths. The estimated number of overdose deaths ranged from 734 to 1,202 per year depending on which definition was used. Of deaths identified using the CDC definition, between 6.4 percent and 16.1 percent were pharmaceutical adverse events that showed no evidence of controlled substance involvement. However, there were 12 additional deaths per year that appeared to be overdoses involving controlled substances that were not identified. The authors propose a definition that includes 28 deaths from substance use disorders, but removes 88 deaths from adverse events, resulting in 1,149 deaths per year on average from overdoses involving controlled substances.