Predictors of Suicide Mortality in Post-9/11 Veterans 1-Year after Military Separation

Background and Purpose: Suicide risk is high among service members transitioning out of the military and after military separation. The military-to-veteran transition is a vulnerable period characterized by life stressors, psychosocial problems, and debilitating symptomatology. This transition is a gap in social support and access to care that increases suicide risk because veterans have limited interaction with military peers, discontinued access to MHS care, and may have not begun using VHA care. This study identified risk and protective factors predicting suicide mortality among post-9/11 veterans up to one year after military separation.

Methods: This retrospective cohort study from the Long-Term Impact of Military-Relevant Brain Injury Consortium Phenotype Study included veterans who served post-9/11, received >3 years of Military Health System (MHS) care, and separated from military service before October 1, 2016. Cause of death was assessed at 1-year post-separation. Using a competing risk approach, a Cox proportional hazard model estimated risk for suicide mortality 1-year post-separation after controlling for continuity of care measures (transition to VHA care within 1-year post-separation, use of MHS post-separation, using VHA care before separation), demographics, military, deployment, physical and mental health diagnoses, and multimorbidity two years before military separation and any psychiatric hospitalizations during military service. The competing event was all other caused mortality. No mortality was the censored event.

Results: Among 1,594,869 veterans, 1713 (0.11%) died within one-year post-separation; 441(3.9%) by suicide an average of 5.2 months post-separation; 50.6% of suicide decedents had transitioned to VHA care. Death for other causes occurred an average of 5.6 months post-separation. The most prevalent conditions among decedents were smoking history and back and neck pain. The strongest predictors of suicide mortality were cognitive-related diagnoses (HR: 1.86, 95% CI: 1.25-2.75), treatment for suicidality two years before separation (HR: 1.78, 95% CI: 1.23-2.62), and serious mental illness (schizophrenia and bipolar; HR: 1.72, 95% CI: 1.19-2.46). Protective factors included use of MHS care post-separation (HR: 0.06, 95% CI 0.05-0.08) and female sex (HR: 0.31, 95% CI: 0.20- 0.50). Psychiatric hospitalization during military service was not associated with suicide mortality.

Conclusions and Implications: Most suicide deaths occurred less than 6 months post-separation. By reducing suicide mortality risk by 94%, continued use of MHS care post-separation was the most significant protective factor. Findings suggest the military-to-veteran transition is a critical period for suicide preventive intervention and linkage to care. Promising suicide prevention strategies may include targeting modifiable risk and protective factors such as risky drinking, drug misuse, cognitive complaints, continuity of MHS care post-separation, and intensive post-discharge case management for service members with a recent history of suicidality. Additional research is needed on the relationship between psychiatric hospitalization and suicide mortality.