Regular Research Articles
Impact of Medicare Part D on Antidepressant Treatment, Medication Choice, and Adherence Among Older Adults With Depression

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Objectives

Depression in older adults is often undertreated due, in part, to medication costs. We examined the impact of improved prescription drug coverage under Medicare Part D on use of antidepressants, medication choice, and adherence.

Design, Setting and Participants

Observational claims-based study of older adults with depression (ICD-9: 296.2, 296.3, 311, 300.4) continuously enrolled in a Medicare managed care plan between 2004 and 2007. Three groups with limited ($150 or $350 quarterly caps) or no drug coverage in 2004–2005 obtained Part D benefits in 2006. A comparison group had stable employer-sponsored coverage throughout.

Measurements

Any antidepressant prescription fill, antidepressant choice (tricyclics or monoamine oxidase inhibitors versus newer antidepressants), and adherence (80% of days covered) in the first 6 months of treatment.

Results

Part D was associated with increased odds of any antidepressant use among those who previously lacked coverage (odds ratio [OR] 1.61, 95% confidence interval [CI] 1.41–1.85) but odds of use did not change among those with limited prior coverage. Use of older antidepressant agents did not change with Part D. All three groups whose coverage improved with Part D had significantly higher odds of 80% of days covered with an antidepressant (OR = 1.86 [95% CI: 1.44–2.39] for no coverage, 1.74 [95% CI: 1.25%3.42] for $150 cap; and 1.19 [95% CI: 1.06–1.34] for the $350 cap groups).

Conclusions

Medicare Part D was associated with improvements in antidepressant use and adherence in depressed older adults who previously had no or limited drug coverage but not with changes in use of older agents. use and adherence in depressed older adults who previously had no or limited drug coverage but not with changes in use of older agents.

Section snippets

Study Design and Source of Data

This study was approved by the University of Pittsburgh institutional review board. The source of data was a large health insurance company in Pennsylvania that offered a variety of insurance plans to Medicare beneficiaries. We obtained prescription drug, medical claims, and enrollment data from the company's Medicare Advantage managed care plans for 2004–2007. Older adults enrolled with this insurance company had one of four types of drug coverage before Part D. Two groups, who enrolled in

Characteristics of the Study Sample

The characteristics of the study sample are presented in Table 1. The groups with limited or no drug coverage prior to Part D were slightly older (mean age 76.84, 76.06, and 75.47 in the No coverage, $150 and $350 cap groups, respectively, compared to 74.21 in the employer group, analysis of variance, df = 1, p <0.05). The groups with $150 and $350 quarterly caps were more likely than the employer group to be woman (78.48% and 75.68%, respectively, versus 68.21%, χ2, df = 1, p <0.05). The three

DISCUSSION

Our study is the first to examine the impact of the new Medicare drug benefit on likelihood of antidepressant treatment, medication choice and refill adherence for older adults with depression who previously lacked or had minimal drug coverage.

Part D was associated with an increased likelihood of antidepressant treatment among older adults diagnosed with depression, who previously lacked drug coverage. This result is consistent with a major goal of Part D, to reduce financial barriers to

References (32)

  • KZ Bambauer et al.

    Depression and cost-related medication nonadherence in Medicare beneficiaries

    Arch Gen Psychiatry

    (2007)
  • Kaiser Family Foundation

    Medicare Chartbook 2005

    (2005)
  • Kaiser Family Foundation

    Fact Sheet: The Medicare Prescription Drug Benefit, Kaiser Family Foundation

    (2008)
  • Zhang Y, Lave JR, Newhouse JP, et al.: How the medicare Part D drug benefit changed the distribution of out-of-pocket...
  • Y Zhang et al.

    The effect of medicare part D on drug and medical spending

    N Engl J Med

    (2009)
  • FR Lichtenberg et al.

    The impact of medicare part D on prescription drug use by the elderly

    Health Aff

    (2007)
  • Cited by (0)

    Presented in part at the Academy Health Annual Research Meeting, Washington, District of Columbia, June 10, 2008; and the American Society of Health Economists meeting in Durham, North Carolina, June 25, 2008.

    Drs Lave and Zhang are investigators for a project in part funded by Highmark Inc (a Medicare-Advantage plan) to evaluate the economic impact of high-deductible health plan on medical care spending. Dr. Reynolds receives pharmaceutical supplies for his NIH-sponsored research from Pfizer, Forest, BMS, Wyeth, and Lilly.

    This publication was supported by the National Center for Research Resources, National Institutes of Health (NIH) (KL2 RR-024154-04), Agency for Healthcare Research and Quality (R01HS017695), NIH grants (R34 MH082682, R01AG027017, P30AG024827, P30MH71944, T32AG021885, K07AG033174, R01AG034056), the Veterans Administration Health Services Research and Development Service (IIR-06-062), the UPMC endowment in geriatric psychiatry, and John A. Hartford Foundation.

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