OBJECTIVES : To explore the population health impact of depression and generalized anxiety disorder (GAD) on the quality of life of Medicare patients at increased risk of hospitalization enrolled in population health management program. The study potentially helps guide the allocation of scarce resources to address mental health issues in this population.

METHODS : Levels of depression and GAD, measured by the patient health questionnaire 9-item depression scale (PHQ-9), the 7-item generalized anxiety disorder scale (GAD-7), and the mental health component of the 12-item short-form health survey (SF-12), were analyzed among 2000 Medicare recipients within the Comprehensive Care Physician (CCP) study. The per capita impact was calculated as the difference between SF-12 scores by level of severity compared to those with minimal levels of depression and GAD. To calculate the population health impact of improving depression and GAD, the SF-12 score differences of each level were multiplied by the prevalence in each level.

RESULTS : The SF-12 score decreases with the severity of both depression and GAD. The score for CCP patients with minimal depression and minimal GAD is 55. The score for CCP patients with severe depression and severe GAD is 29. The per capita impact indicates patients would need to improve their SF-12 score by 26 to improve their depression and GAD level from severe to minimal. The population health impact indicates 25% of CCP patients need to improve their mental state from severe GADs crossing five severity levels of depression to minimum depression and GAD.

CONCLUSIONS : Psychiatrists and health decision makers could utilize the average per capita benefit to improve overall quality of life by calculating how many SF-12 scores need to be improved. The population health impact provides straightforward view of the population distribution in the CCP study that needs to be improved and could guide resource allocation associated with depression and GAD.