Influence of depression on racial and ethnic disparities in diabetes control

We tested the hypotheses that depression diagnoses influence racial and ethnic disparities in diabetes control and that mental health treatment moderates that relationship.

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.

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.

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.