Effects of Medicare Part D coverage gap on medication and medical treatment among elderly beneficiaries with depression.

Context: Maintenance antidepressant pharmacotherapy in late life prevents recurrent episodes of major depression. The coverage gap in Medicare Part D could increase the likelihood of reducing appropriate use of antidepressants, thereby exposing older adults to an increased risk for relapse of depressive episodes.

Objectives: To determine whether (1) beneficiaries reduce antidepressant use in the gap, (2) the reduction in antidepressant use is similar to the reduction in heart failure medications and antidiabetics, (3) the provision of generic coverage reduces the risk of reduction of medication use, and (4) medical spending increases in the gap.

Design: Observational before-after study with a comparison group design.

Setting And Patients: A 5% random sample of US Medicare beneficiaries 65 years or older with depression (n = 65,223) enrolled in stand-alone Part D plans in 2007.

Main Outcome Measures: Antidepressant pharmacotherapy, physician, outpatient, and inpatient spending.

Results: Being in the gap was associated with comparable reductions in the use of antidepressants, heart failure medications, and antidiabetics. Relative to the comparison group (those who had full coverage in the gap because of Medicare coverage or low-income subsidies), the no-coverage group reduced their monthly antidepressant prescriptions by 12.1% (95% CI, 9.9%-14.3%) from the pregap level, whereas they reduced use of heart failure drugs and antidiabetics by 12.9% and 13.4%, respectively. Those with generic drug coverage in the gap reduced their monthly antidepressant prescriptions by 6.9% (95% CI, 4.8%-9.1%); this decrease was entirely attributable to the reduction in the use of brand-name antidepressants. Medicare spending on medical care did not increase for either group relative to the comparison group.

Conclusions: The Medicare Part D coverage gap was associated with modest reductions in the use of antidepressants. Those with generic coverage reduced their use of brand-name drugs and did not switch from brand-name to generic drugs. The reduction in antidepressant use was not associated with an increase in nondrug medical spending.