25620439

PMC4390474

Purpose

Black patients with diabetes are at greater risk for underuse of antidepressants even when they have equal access to health insurance. This study aims to evaluate the impact of removing a significant financial barrier to prescription medications (drug caps) on existing black-white disparities in antidepressant treatment rates among patients with diabetes and comorbid depression.

Methods

We used an interrupted time series with comparison series (ITS) design and a 5% representative sample of all fee-for-service Medicare and Medicaid dual enrollees to evaluate the removal of drug caps on monthly antidepressant treatment rates. We evaluated the impact of drug cap removal on racial gaps in treatment by modeling the month-to-month white-black difference in use within age strata (<65, 65 or older). We compared adult dual enrollees with diabetes and comorbid depression living in states with strict drug caps (n=221) and without drug caps (n=1133) prior to the policy change.

Findings

The removal of drug caps in strict cap states was associated with a sudden increase in the proportion treated for depression (4 percentage points; 95% Confidence Interval: 0.03, 0.05, <0.0001) and in the intensity of antidepressant use (SMD: 0.05; 95% CI: 0.03, 0.07, p<0.001). While antidepressant treatment rates increased for both whites and blacks, the white-black treatment gap increased immediately after Part D [0.04 percentage points; 95% CI: 0.01, 0.08] and grew over time [0.04 percentage points per month (0.002, 0.01); P<0.001].

Implications

Policies that remove financial barriers to medicines may increase depression treatment rates among patients with diabetes overall while exacerbating treatment disparities. Tailored outreach may be needed to address non-financial barriers to mental health services use among African Americans with diabetes.

CDC Public Access

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U58DP002721/DP/NCCDPHP CDC HHS/United States