3129 — Suicidal Ideation as Indicated by the PHQ-9: Assessing Associations with Suicide Mortality Among Veterans Health Administration Patients

Louzon SA, Office of Mental Health Operations; Bossarte RM, Office of Public Health; McCarthy JF, Office of Mental Health Operations; Katz IR, Office of Mental Health Operations;

Objectives:
The Veterans Health Administration (VHA) health system mandates annual depression screens for all patients who are not receiving treatment for depression or bipolar disorder. The nine-item Patient Health Questionnaire (PHQ-9) is used by some providers for routine assessments and is recommended for patients with positive depression screens. Endorsement of item 9 of the PHQ-9, regarding frequency of thoughts of being better off dead or of self-harm, has been positively associated with suicide mortality among patients in a non-VHA health system. To inform VHA suicide prevention activities, it is important to evaluate whether item 9 is associated with suicide risk among patients in the VHA health system.

Methods:
For 447,245 PHQ-9 assessments, conducted between 10/1/2009-9/30/2010 (FY2010) for 391,492 VHA patients, we used National Death Index data to ascertain suicide mortality from the date of assessment through 9/30/2011. Using multivariable partly conditional proportional hazards regression, we evaluated associations between responses to item 9 of the PHQ-9 and suicide mortality. Analyses adjusted for age, sex, mental health diagnoses, PHQ-9 items 1-8, and treatment setting on the assessment date. Covariance sandwich estimators adjusted for the nested nature of the data. Supplemental analyses assessed differences in suicide rates by patient receipt of documented PHQ-9 assessments.

Results:
310 suicide deaths occurred in the study period. Adjusting for covariates, endorsement of item 9 was associated with a 44% increased suicide risk for every unit increase (HR: 1.44, 95% CI: 1.26-1.66). Greater suicide rates were observed among VHA patients in FY2010 who had documented PHQ-9 assessments as compared to those who did not (53.3 vs. 37.0 per 100,000 person-years).

Implications:
Greater endorsement of item 9 of the PHQ-9 was associated with increased risk of suicide among VHA patients with documented PHQ-9 assessments, a subpopulation that has elevated suicide risk.

Impacts:
Findings underscore the importance of suicide prevention protocols for individuals who endorse item 9 of the PHQ-9.