Drug overdose mortality among healthcare system patients and publicly and privately insured people in North Carolina, USA: 2014–2022

Background The drug overdose epidemic—responsible for approximately 108 000 deaths in the USA in 2022 and imposing a substantial economic burden—underscores the need to better understand population-specific risks. We compared overdose mortality rates in North Carolina across three cohorts—healthcare system patients, privately insured individuals and Medicaid enrollees—from 2014 to 2022. Methods Data from large integrated datasets for populations of interest were linked with death certificate records for 2014–2022. Overdose deaths involving all-drug, opioids or polydrugs were identified using International Classification of Disease Version 10 codes for primary and contributing cause of death among individuals aged 12–64. Using North Carolina population as the reference, age-, sex- and calendar year-adjusted overdose mortality rates and standardised mortality ratios were respectively calculated through direct and indirect standardisation. Results In North Carolina general population, overdose mortality rates per 100 000 person-years for all-drug, opioids and polydrugs were 28.8, 25.0 and 18.0 respectively. Among healthcare system patients, the corresponding adjusted rates were substantially higher—105.2, 86.4 and 62.8 (standardised mortality ratios: 3.4, 3.2, 3.3). Medicaid enrollees also had elevated rates—85.4, 63.6 and 46.4 (standardised mortality ratios: 2.8, 2.4, 2.4). In contrast, privately insured individuals had lower rates—16.1, 12.3 and 8.6 (standardised mortality ratios: 0.5, 0.5, 0.5). Conclusions Individuals receiving care within the health system experienced the highest overdose mortality rates, followed by those with Medicaid coverage, with both exceeding rates observed among privately insured individuals. These findings highlight significant socioeconomic health inequalities that could benefit from targeted overdose prevention interventions among resource-limited populations.