Background and aims: While mortality rates after prison release are high, little is known about clinical risk factors for death. We sought to identify risk and protective factors for all-cause and accidental poisoning (overdose) death.
Design: Nested case-control study of people released from prison.
Setting: Washington State Department of Corrections, Washington, USA.
Participants: Cases (699 all-cause deaths, of which 88 were among women, and 196 additional overdose deaths, of which 76 were among women) between 1999 and 2009 matched 1 : 1 to controls on sex, age and year of release using risk set sampling.
Measurements: Prison medical charts were abstracted for clinical information. Independent associations between clinical characteristics and all-cause and overdose mortality were assessed using conditional logistic regression.
Findings: Key independent risk factors for all-cause mortality included homelessness [odds ratio (OR) = 1.53, 95% confidence interval (CI) = 1.06, 2.23], injection drug use (OR = 1.54, 95% CI = 1.16, 2.06), tobacco use (OR = 1.51, 95% CI = 1.07, 2.13), cirrhosis (OR = 4.42, 95% CI = 1.63, 11.98) and psychiatric medications before release (OR = 2.38, 95% CI = 1.71, 3.30). Independent risk factors for overdose mortality included substance use disorder (OR = 2.33, 95% CI = 1.32, 4.11), injection drug use (OR = 2.43, 95% CI = 1.53, 3.86), panic disorder (OR = 3.87, 95% CI = 1.62, 9.21), psychiatric prescriptions before release (OR = 2.44, 95% CI = 1.55, 3.85) and problems with opiates/sedatives (OR = 2.81, 95% CI = 1.40, 5.63). Substance use disorder treatment during the index incarceration was protective for all-cause (OR = 0.67, 95% CI = 0.49, 0.91) and overdose (OR = 0.57, 95% CI = 0.36, 0.90) mortality.
Conclusions: Injection drug use and substance use disorders are risk factors for death after release from prison. In-prison substance use disorder treatment services may reduce the risk.