Validation of the PHQ-9 for Suicidal Ideation in Persons with Inflammatory Bowel Disease

Background: Suicide is a leading cause of death worldwide. Transition from suicidal ideation (SI) to suicide attempt is high within a year of SI onset. The risk of suicide and SI is elevated in persons with inflammatory bowel disease (IBD) versus the general population. We aimed to validate the Patient Heath Questionnaire (PHQ)-9 as a screening tool for SI in IBD and to determine factors associated with SI in IBD. Methods: IBD participants (n = 247) recruited from the community and clinics completed the PHQ-9 and participated in the Structured Clinical Interview for DSM-IV (SCID). We determined the sensitivity, specificity, and positive and negative predictive value (PPV and NPV) of the PHQ-9 in identifying SI as compared to the SCID. Using logistic regression we examined the association of SI with demographic and clinical factors. Results: SI was endorsed by 24 (9.7%) participants on the PHQ-9 and 5 (2.0%) based on the SCID. The PHQ-9 had good sensitivity (100%), specificity (92.2%), and NPV (100%) but low PPV (20.8%) for SI. On univariate analysis, factors strongly associated with SI were depression (OR 13.1; 95% CI: 4.46, 40.5), anxiety (OR 11.3; 95% CI: 4.46, 28.6), and active disease (OR 3.87; 95% CI: 1.54, 9.71). On multivariable analysis, depression (OR 5.54; 95% CI: 1.67, 18.4) and pain (OR 1.14; 95% CI: 1.03, 1.25) were associated with SI. Conclusions: Overall the PHQ-9 is a valid screening tool for SI in IBD patients, and routine implementation of this tool would support screening for depression and SI effectively and efficiently in clinical practice.