High-risk emergency department visits and risk of all-cause mortality, suicide, and fatal overdose among US military veterans.

Deaths due to overdose and suicide together comprise an urgent public health challenge. Using Veterans Health Administration (VHA) electronic health records, we identified patients with high-risk emergency department (ED) visits related to suicidality or overdose between January 2010 and September 2019 using diagnostic codes from the International Classification of Diseases. We calculated standardized mortality ratios (SMR) for 90-day all-cause and cause-specific mortality associated with high-risk VHA ED visits compared with other VHA ED users, all VHA users, and the US general population. Among 20 382 060 ED visits from 3 705 984 unique Veterans, we identified 318 950 high-risk ED visits. The 90-day all-cause mortality rate among Veterans with high-risk ED visits was 2.81 times the expected rate (95% CI, 2.72-2.92) for other VHA ED users after adjusting for sex, race, and age. Rates remained elevated compared to all VHA users and the US general population. By race, mortality rates were markedly elevated among veterans identified as Asian or Pacific Islander (SMR = 3.50, 95% CI, 2.86-4.24) compared to other VHA ED users. The 90-day cause-specific SMRs were most pronounced for suicide, overdose, and accidents or unintentional self-harm. These results suggest that high-risk ED visits should trigger assertive, continued mental health care directed at reducing acute mortality through structured suicide prevention programs.