Importance: Identification of subgroups at greatest risk for suicide mortality is essential for prevention efforts and targeting interventions. Sexual minority individuals may have an increased risk for suicide compared with heterosexual individuals, but a lack of sufficiently powered studies with rigorous methods for determining sexual orientation has limited the knowledge on this potential health disparity.

Objective: To investigate suicide mortality among sexual minority veterans using Veterans Health Administration (VHA) electronic health record data.

Design, setting, and participants: This retrospective population-based cohort study used data on 8.1 million US veterans enrolled in the VHA after fiscal year 1999 that were obtained from VHA electronic health records from October 1, 1999 to September 30, 2017. Data analysis was carried out from March 1, 2020 to October 31, 2020.

Exposure: Veterans with documentation of a minority sexual orientation. Documentation of sexual minority status was obtained through natural language processing of clinical notes and extraction of structured administrative data for sexual orientation in VHA electronic health records.

Main outcomes and measures: Suicide mortality rate using data on the underlying cause of death obtained from the National Death Index. Crude and age-adjusted mortality rates were calculated for all-cause death and death from suicide among sexual minority veterans compared with the general US population and the general population of veterans.

Results: Among the 96 893 veterans with at least 1 sexual minority documentation in the electronic health record, the mean (SD) age was 46 (16) years, 68% were male, and 70% were White. Of the 12 591 total deaths, 3.5% were from suicide. Veterans had a significantly higher rate of mortality from suicide (standardized mortality ratio, 4.50; 95% CI, 4.13-4.99) compared with the general US population. Suicide was the fifth leading cause of death in 2017 among sexual minority veterans (3.8% of deaths) and the tenth leading cause of death in the general US population (1.7% of deaths). The crude suicide rate among sexual minority veterans (82.5 per 100 000 person-years) was higher than the rate in the general veteran population (37.7 per 100 000 person-years).

Conclusions and relevance: The results of this population-based cohort study suggest that sexual minority veterans have a greater risk for suicide than the general US population and the general veteran population. Further research is needed to determine whether and how suicide prevention efforts reach sexual minority veterans.