Overdose and substance-related mortality after release from prison in Washington State: 2014-2019

Background: Persons released from prison are at an increased risk of mortality compared to the non-incarcerated population, particularly from drug- and opioid-related overdose. Contributors to overdose mortality vary with changing patterns of substance use and updating overdose and mortality statistics may help focus resources for persons released from prison. Methods: In this retrospective cohort study, records for 33,811 people released from Washington State Department of Corrections prisons between 2014 and 2018 were linked to Washington State death records from 2014 to 2019. We calculated post-release mortality rates by cause of death, including overdose and substance-related mortality. Hazard ratios for risk factors for all-cause, non-overdose, and overdose mortality were estimated using Cox proportional hazards regression. Results: 862 deaths were identified among persons released from prison. The all-cause mortality rate was 747 per 100,000 person-years (95 % CI: 699-800), and drug overdose was the leading cause of death (216 per 100,000 person-years; 95 % CI: 190-244). Psychostimulant-related mortality (152 per 100,000 person-years; 95 % CI: 131-177) and opioid-related mortality (138 per 100,000 person-years; 95 % CI: 118-161) were the most prevalent among substance-related causes of death, with the greatest mortality risk occurring within two weeks after release. Older age at most recent release, previous incarceration, and drug-related convictions were significant risk factors for all-cause and overdose mortality within six years after release. Conclusions: Psychostimulants were the greatest contributors to substance-related mortality for persons released from Washington State prisons. Greater efforts to prevent psychostimulant- and opioid-related overdose are needed.