Influence of depression on racial and ethnic disparities in diabetes control

INTRODUCTION: We tested the hypotheses that depression diagnoses influence racial and ethnic disparities in diabetes control and that mental health treatment moderates that relationship. RESEARCH DESIGN AND METHODS: We created a national cohort of Veterans Health Administration (VHA) patients with diabetes using administrative data (n=815 067). Cross-sectional linear mixed effects regression models tested the hypothesized indirect effect of depression on poor diabetes control (glycosylated hemoglobin >9%) and tested whether mental health treatment (visits or antidepressant prescriptions) moderated the effect of depression (α=0.05). Results represent the percentage point difference in probability of poor diabetes control. Covariates included primary care visits, sex, age, and VHA facility. RESULTS: Overall, 20% of the cohort had poor diabetes control and 22% had depression. Depression was more common among racial and ethnic minoritized groups. The probability of poor diabetes control was higher for most minoritized groups compared with White patients (largest difference: American Indian or Alaska Native patients, 5.2% (95% CI 4.3%, 6.0%)). The absolute value of the proportion of racial and ethnic disparities accounted for by depression ranged from 0.2% (for Hispanic patients) to 2.0% (for Asian patients), with similar effects when accounting for the moderating effect of mental health treatment. Patients with depression and 5+ mental health visits had a lower probability of poor diabetes control compared with those with fewer visits, regardless of antidepressant prescription status. CONCLUSIONS: The influence of depression on disparities in diabetes control was small. High rates of depression among people with diabetes, especially among those from racial and ethnic minoritized groups, highlight a need to ensure equitable and coordinated care for both conditions, as the effects of mental health treatment may extend to the control of physical health conditions.