June 2010, Volume 25, Issue 6, pp 568-574,
Open Access This content is freely available online to anyone, anywhere at any time.
Date: 09 Mar 2010
Entering and Exiting the Medicare Part D Coverage Gap: Role of Comorbidities and Demographics
Some Medicare Part D enrollees whose drug expenditures exceed a threshold enter a coverage gap with full cost-sharing, increasing their risk for reduced adherence and adverse outcomes.
To examine comorbidities and demographic characteristics associated with gap entry and exit.
We linked 2005–2006 pharmacy, outpatient, and inpatient claims to enrollment and Census data. We used logistic regression to estimate associations of 2006 gap entry and exit with 2005 medical comorbidities, demographics, and Census block characteristics. We expressed all results as predicted percentages.
287,713 patients without gap coverage, continuously enrolled in a Medicare Advantage Part D (MAPD) plan serving eight states. Patients who received a low-income subsidy, could not be geocoded, or had no 2006 drug fills were excluded.
Of enrollees, 15.9% entered the gap, 2.6% within the first 180 days; among gap enterers, only 6.7% exited again. Gap entry was significantly associated with female gender and all comorbidities, particularly dementia (39.5% gap entry rate) and diabetes (28.0%). Among dementia patients entering the gap, anti-dementia drugs (donepezil, memantine, rivastigmine, and galantamine) and atypical antipsychotic medications (risperidone, quetiapine, and olanzapine) together accounted for 40% of pre-gap expenditures. Among diabetic patients, rosiglitazone accounted for 7.2% of pre-gap expenditures. Having dementia was associated with twice the risk of gap exit.
Certain chronically ill MAPD enrollees are at high risk of gap entry and exposure to unsubsidized medication costs. Clinically vulnerable populations should be counseled on how to best manage costs through drug substitution or discontinuation of specific, non-essential medications.
Federal Register. Medicare Program Part D Final Rule, Medicare drug benefit effective CY 2006 (Title 1). Fed Regist [Rules and Regulations], Jan 28, 2005. 70:4193–4585. Available at: http://edocket.access.gpo.gov/2005/pdf/05-1321.pdf. Accessed January 15, 2010.
Frakt AB, Pizer SD. A first look at the new Medicare Prescription Drug Plans. Health Aff (Millwood). 2006;25:w252–61.CrossRef
Hoadley J, Hargrave E, Merrell K, Cubanski J, Neuman T. Benefit design and formularies of Medicare Drug Plans: a comparison of 2006 and 2007 offerings (Menlo Park, Calif.: Henry J. Kaiser Family Foundation, Nov. 2006). Available at: http://www.kff.org/Medicare/upload/7589.pdf. Accessed: January 15, 2010.
Summer L, Nemore P, Finberg J. Improving the Medicare Part D Program for the most vulnerable beneficiaries. 2007 May. Available at: http://www.commonwealthfund.org/publications/publications_show.htm?doc_id=484282. Accessed January 15, 2010.
Pauly MV. Medicare drug coverage and moral hazard. Health Aff (Millwood). 2004;23(1):113–22.CrossRef
The Henry J. Kaiser Family Foundation. Medicare Part D 2008 data spotlight: premiums, November 2007. Available at: http://www.kff.org/Medicare/7706.cfm. Accessed January 15, 2010.
IMS. IMS Special Report, Medicare Part D: The first year. Plymouth Meeting, PA. IMS Health, Inc; 2008.
Stuart B, Simoni-Wastila L, Chauncey D. Assessing the impact of coverage gaps in the Medicare Part D drug benefit. Health Aff (Millwood). 2005;Suppl Web Exclusives:W5-167-W5-179.
Daniel GW, Malone DC. Characteristics of older adults who meet the annual prescription drug expenditure threshold for Medicare medication therapy management programs. J Manag Care Pharm. 2007;13(2):142–54.PubMed
HCUP. Healthcare Cost and Utilization Project. Clinical Classifications Software (CCS) for ICD-9-CM. Agency for Healthcare Research and Quality 2008. http://www.hcup-us.ahrq.gov/toolssoftware/ccs/ccs.jsp#download. Accessed January 15, 2010.
King G, Tomz M, Wittenberg J. Making the most of statistical analyses: improving interpretation and presentation. Am J Polit Sci. 2000;44:341–55.CrossRef
U.S Census Bureau, Population Division. Annual estimates of the population by sex and five-year age groups for the United States: April 1, 2000 to July 1, 2007. May 2008. Available at: http://www.census.gov/popest/datasets.html. Accessed January 15, 2010.
Federal Interagency Forum on Aging-Related Statistics. Older americans update 2006: key indicators of well-being. U.S.Government Printing Office, Washington, DC, May 2006.
Fung V, Mangione CM, Huang J, et al. Falling into the coverage gap: Part D drug costs and adherence for Medicare Advantage Prescription Drug Plan beneficiaries with diabetes. Health Services Research; Under revise and resubmit, 2009.
Loveman E, Green C, Kirby J, et al. The clinical and cost-effectiveness of donepezil, rivastigmine, galantamine and memantine for Alzheimer's disease. Health Technol Assess. 2006;10(1):iii-iv, ix-xi, 1–160.
Raina P, Santaguida P, Ismaila A, et al. Effectiveness of cholinesterase inhibitors and memantine for treating dementia: evidence review for a clinical practice guideline. Ann Intern Med. 2008;148(5):379–97.PubMed
U.S. Food and Drug Administration. Public Health Advisory: Deaths with Antipsychotics in Elderly Patients with Behavioral Disturbances, April 11, 2005. Available at: http://www.fda.gov/Drugs/DrugSafety/PublicHealthAdvisories/ucm053171.htm. Accessed January 31, 2010.
Robinson JC. Physician organization in California: crisis and opportunity. Health Aff (Millwood). 2001;20(4):81–96.CrossRef
Patel RA, Lipton HL, Cutler TW, Smith AR, et al. Cost minimization of Medicare part D prescription drug plan expenditures. Am J Manag Care. 2009;15(8):545–53.PubMed
Lexchin J. Effects of restrictive formularies in the ambulatory care setting. Am J Manag Care. 2002;8(1):69–76.PubMed
Burt CW, Sisk JE. Which physicians and practices are using electronic medical records? Health Aff (Millwood). 2005;24(5):1334–43.CrossRef
- Entering and Exiting the Medicare Part D Coverage Gap: Role of Comorbidities and Demographics
- Open Access
- Available under Open Access This content is freely available online to anyone, anywhere at any time.
Journal of General Internal Medicine
Volume 25, Issue 6 , pp 568-574
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- 1. Division of General Internal Medicine and Health Services Research, Department of Medicine, David Geffen School of Medicine at UCLA, 911 Broxton Plaza, Los Angeles, CA, 90024, USA
- 2. Department of Health Services, UCLA School of Public Health, Los Angeles, CA, USA
- 3. Division of Research, Kaiser Permanente Medical Care Program, Northern California, Oakland, CA, USA