OBJECTIVES : Patient Health Questionnaire-9 (PHQ-9) is a validated tool used to assist clinicians in assessing depression severity. This study’s objective was to characterize treatment for depression and healthcare expenditures among patients administered the PHQ-9.

METHODS : Adult patients with PHQ-9 score between 1/1/2011 and 9/30/2016 were identified using MarketScan Claims and Electronic Medical Records Database (CED). The first PHQ-9 was the index date; 12 months continuous enrollment before and after the index date was required. Depression severity, assessed via PHQ-9 scores, was categorized as minimal (<5), mild (5-9), moderate (10-14), or severe (>14). Depression treatment and all-cause healthcare expenditures during follow-up were assessed and stratified by presence of a pre-existing mental health (MH) diagnosis.

RESULTS : 11,066 patients met inclusion criteria; mean patient age was 66 years and 56% of patients were female. 11% of patients had PHQ-9 scores indicating depression (4% mild, 4% moderate, and 3% severe). Patients with a pre-existing MH diagnosis (19%) reported more severe depression compared to those without a pre-existing MH diagnosis (MH: 6% mild, 7% moderate, 6% severe; no MH: 3% mild, 3% moderate 3% severe; p<0.001 for all). Antidepressant treatment was more common in patients with severe depression during follow-up; those with a pre-existing MH diagnosis had the highest rates of treatment (MH: 56% minimal, 76% mild, 83% moderate, 82% severe; no MH: 14% minimal, 48% mild, 62% moderate, 76% severe; p<0.001 for all). Mean all-cause expenditures were similar in patients with mild ($14,983), moderate ($15,403), and severe depression ($15,046); expenditures for each group were significantly higher than expenditures in patients with minimal depression ($11,161; p<0.001 for all).

CONCLUSIONS : Though 7% patients had severe or moderate depression, a significant proportion received no antidepressant therapy which may represent unmet need. Further research is needed to understand barriers for depression treatment and the impact on healthcare costs.