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Datawatch |
Medication Costs, Adherence, And Health Outcomes Among Medicare Beneficiaries
| Abstract |
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In a two-year period more than two million elderly Medicare beneficiaries did not adhere to drug treatment regimens because of cost. This poor adherence tended to be more common among beneficiaries with no or partial medication coverage and was associated with poorer health and higher rates of hospitalization. The risk for cost-related poor adherence was especially pronounced among lower-income beneficiaries with high out-of-pocket drug spending. We argue that this pattern of cost-related poor medication adherence should inform the design of Medicare prescription drug benefit legislation.
Rapidly rising prescription drug costs have raised concerns over access for older Americans. Although Medicare covers most of the elderly, the traditional Medicare benefit package does not cover outpatient prescription drugs. Many beneficiaries have some drug coverage through employer-sponsored supplemental insurance, individually purchased Medigap plans, Medicare health maintenance organization (HMO) plans, or public programs such as Medicaid and state pharmacy programs. However, there has been a recent decline in these sources of supplemental coverage.1 Approximately ten million Medicare beneficiaries have no prescription drug coverage.2 Without governmental intervention, this number is likely to grow.
Despite widespread public attention to this issue, little information exists concerning the use of medications and health outcomes among Medicare beneficiaries without prescription drug coverage. Some evidence suggests that elderly beneficiaries who do not have drug coverage use fewer prescription drugs, forgo filling their prescriptions, skip doses, or use lower doses than prescribed, because of the cost of medications.3 However, the association of cost-related poor medication adherence with health outcomes in representative samples of Medicare beneficiaries remains unexamined.
In this paper we use data from a recent national household survey of older Americans to examine the association of prescription drug coverage with adherence to medications prescribed for various chronic conditions and the association of cost-related poor adherence with health outcomes. We also examine the prevalence of poor adherence among beneficiaries at different income levels and with different levels of out-of-pocket spending.
| Study Methods |
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 Top Study Methods Study ResultsDiscussion And Policy...Editor's NotesNOTES |
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Sample. The data come from the most recent wave (2000) of the Health and Retirement Study (HRS), an ongoing longitudinal survey of community-dwelling older Americans.4 The HRS sampled household residents in the forty-eight contiguous states using a multistage area probability sampling design. The first wave of the HRS included participants born in 1931–1941. It was conducted in 1992 and has been repeated every two years since. In addition to the original cohort, new cohorts are added to provide coverage of the whole age range of U.S. elderly.5 The response rate at the 1992 interview was 78 percent. Nonrespondent households were more likely to be white, married, in good physical and mental health, and currently working and were less likely to have public health insurance. Nonrespondents also had more financial assets and higher incomes. These factors were taken into account in computing analytic weights used here. A total of 19,581 participants were interviewed in 2000. We focus on the 10,413 participants age sixty-five and older who were enrolled in Medicare in 2000. Nearly four-fifths of the interviews were conducted by telephone and the rest in person.
Assessment. Specific conditions and medication use. We examined conditions that typically require continuous medication treatment: hypertension, arthritis, cardiovascular disease (including heart attacks and angina), diabetes, psychiatric disorders, and lung disease (excluding asthma). For each condition, participants were asked whether a doctor had ever told them they had the condition, and whether they used medications for each condition.
Office visits, preventive services, and other interventions. Participants were asked about the number of visits to doctors’ offices over the past two years. They also were asked if they had received preventive services during that time, including cholesterol testing, flu shots, mammography or Pap smears for women, and prostate examination for men. A scale was created by summing positive responses (score range, 0–3). Participants who indicated having a heart disease were asked if in the past two years they had received a special test or treatment of their heart "where tubes were inserted into veins or arteries (cardiac catheterization, coronary angiogram, or angioplasty)." They were also asked about heart surgery. Participants with lung disease were asked if they were receiving "respiratory therapy." Finally, respondents with hypertension and diabetes were asked if over the past two years they had "lost weight or followed a special diet" for their condition.
Drug coverage. Participants who indicated that they used medications were asked whether all or some of the costs were covered by insurance. Based on responses, three categories of coverage were constructed: full, partial, and no coverage.
Cost-related poor adherence. Rating of cost-related poor adherence was based on one question. Respondents who reported using medications were asked whether during the past two years they had taken less than prescribed because of cost.
Health ratings. Change in the status of each condition was ascertained by asking participants whether each of their conditions had gotten worse, gotten better, or not changed since the last interview two years ago. Participants with hypertension and diabetes were also asked whether the condition was under control.
General physical symptoms were ascertained by asking participants about seven physical symptoms that had been persistent since the last interview: swollen feet, shortness of breath, dizziness, back pain, headache, severe fatigue or exhaustion, and wheezing. A scale was created by summing the positive responses (score range, 0–7). Depressive symptoms were assessed using a modified eight-item version of the Center for Epidemiologic Studies—Depression Scale (CES-D), developed for the HRS (score range, 0–8).6 Overall perceived health was assessed by a five-point self-rated scale from "excellent" to "poor."
Out-of-pocket spending and household income. Participants who indicated that they used medications were asked about their monthly medication spending. Respondents who could not provide exact amounts were asked to provide estimates. Income was ascertained by asking about household income from various sources during the past year (1999). The relationship of income to the federal poverty level was assessed using the annual federal poverty guidelines for 2000.7
Data analysis. Data analysis was conducted in four stages. (1) Demographic-specific and insurance coverage–specific rates of medication use and out-of-pocket medication spending were calculated. (2) The association of prescription drug coverage with cost-related poor medication adherence was examined by binary logistic regression analyses. A three-tier measure of insurance coverage (full, partial, no coverage) was used to index depth of drug coverage. Age, sex, race, education, and household income were included in these regressions, to adjust for their potential confounding effects. Trends across levels of coverage were also assessed using the score test for trend of odds. (3) The association of cost-related poor medication adherence with health outcomes was examined, using binary logistic regression for dichotomous health outcomes, ordinal logistic regression for the ordinal measure of overall perceived health, and linear regression for continuous outcomes. Age, sex, race, household income, education, and out-of-pocket medication spending were included in these analyses to adjust for their potential effects. To adjust for the effect of overall access to health services, we included number of office visits and access to preventive services in all models predicting health outcomes. We also included weight control and special diet in models predicting outcomes of hypertension and diabetes, catheterization and heart surgery in the model predicting outcome of heart disease, and respiratory therapy in the model predicting outcome of lung disease. These analyses were conducted in the whole sample and repeated in the subsample of participants with incomes of 200 percent of poverty or below. (4) Finally, the prevalence of cost-related poor adherence in patients with various levels of income and out-of-pocket drug spending was examined using descriptive methods. In all analyses, frequency weights, strata, and primary sampling units were used to adjust the parameter estimates and their variances, using Stata 7.0.8
| Study Results |
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| TopStudy MethodsStudy ResultsDiscussion And Policy...Editor's NotesNOTES |
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Sociodemographic characteristics. A majority of the sample was female, white, married, and not employed (Exhibit 1
). The average age was 75.6 years (standard deviation = 7.4). Eighty-three percent (n = 8,704) took prescription medications. Thirteen percent of these (n = 1,320) had full medication coverage, and 61 percent (n = 5,132) partial coverage; the remaining 27 percent (n = 2,218) had no coverage (coverage information for thirty-four participants was missing). All numbers above are unweighted.
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On average, Medicare beneficiaries who took medications spent $73 per month on medications. Out-of-pocket drug spending varied among beneficiaries by supplemental coverage source (Exhibit 1
). Beneficiaries who also had Medicaid coverage spent the least; those with individually purchased supplemental coverage and without any supplemental coverage (traditional Medicare) spent the most.
Drug coverage and poor adherence due to cost.
Chronic health conditions were common among Medicare beneficiaries (Exhibit 2). Forty-eight percent reported taking medications for hypertension, 27 percent for arthritis, 20 percent for heart disease, 13 percent for diabetes (both insulin and oral medications), 6 percent for psychiatric disorders, and 6 percent for lung disease. Overall, among 8,704 beneficiaries using medications for any conditions, 557 (7 percent) reported cost-related poor adherence. This corresponds with more than two million beneficiaries. As shown, lack of drug coverage was associated with cost-related poor adherence.
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Association of poor adherence and health outcomes. We found cost-related poor medication adherence to be related to adverse health outcomes (Exhibits 3
–5). Participants with cost-related poor adherence were more likely than those without it to perceive their overall health as poor (23 percent versus 10 percent, respectively) and to have been hospitalized (43 percent versus 33 percent). They also were more likely to report that their health got worse over the past two years (44 percent versus 30 percent); to report more general physical symptoms (2.4 [SD = 1.9] versus 1.4 [SD = 1.5]); to report worsening of hypertension (7 percent versus 4 percent); to report that hypertension was not controlled (7 percent versus 3 percent); to report worsening of heart disease (21 percent versus 11 percent) and arthritis (49 percent versus 40 percent); and to report higher depressive symptoms (mean CES-D score of 4.5 [SD = 2.0] versus 3.5 [SD = 2.5]). Repeating analyses in the subgroups with income of 200 percent of poverty or less produced similar results (data not shown), with the exception that results for worsening of arthritis and depressive symptoms did not reach statistical significance.
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Relationships between drug spending and adherence across income groups. We also found cost-related poor adherence to be associated with income level and out-of-pocket spending for drugs (Exhibit 6
). Whereas only 7 percent of all Medicare beneficiaries using medications reported cost-related poor adherence, more than 20 percent of low-income beneficiaries with out-of-pocket drug spending of $1,000 or more did so.
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| Discussion And Policy Implications |
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| TopStudy MethodsStudy ResultsDiscussion And Policy...Editor's NotesNOTES |
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More than two million Americans with Medicare coverage had cost-related poor adherence with their medications in 2000. Our results further show that Medicare beneficiaries with higher out-of-pocket medication spending reported higher rates of cost-related poor adherence, which, in turn, adversely affected their health outcomes. Our study also shows that low-income beneficiaries with higher out-of-pocket spending for drugs were especially vulnerable to cost-related poor adherence.
Limitations. This study had several limitations. First, all measures are based on self-reports. Second, our data are cross-sectional. Caution is required in inferring causal relationships from such data. Third, we focused on poor adherence with medications that the participant had already purchased and was using. Another likely effect of lack of drug coverage would be to forgo purchasing prescribed drugs altogether. Therefore, our estimates of the effect of prescription drug coverage on poor adherence are likely conservative. Finally, we did not attempt to assess directly the impact of medication insurance coverage on health outcomes because the potential effects of adverse selection would make the results difficult to interpret.9 People in poorer health simply tend to buy more coverage. Hence, the effect of coverage on health cannot be separated from the effect of health on coverage. Focusing on cost-related poor adherence allowed us to bypass these reciprocal associations and assess the impact of financial barriers to needed medications on health outcomes.
Implications for designing a Medicare drug benefit. This study adds to mounting evidence of the need for a Medicare prescription drug benefit. However, there are few empirical data, beyond overall cost estimates, to guide development of a specific plan. There seems to be a consensus that any such plan should target those in most "need." However, there is little consensus about how to define "need."10
Cost-related poor medication adherence may inform the definition of "need" and provide a justification for prescription drug coverage. We believe that efficient benefit design should give priority to people who without such coverage would be at highest risk of delaying or forgoing the purchase of necessary medications. Thus, an efficient plan should include a sliding-scale copayment schedule, referenced to income and spending, that reduces copayment to zero for the lowest-income beneficiaries with high out-of-pocket spending.11
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| Editor's Notes |
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| TopStudy MethodsStudy ResultsDiscussion And Policy...Editor's NotesNOTES |
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Ramin Mojtabai is an assistant professor of clinical psychiatry and Mark Olfson, an associate professor of clinical psychiatry, in the Department of Psychiatry, College of Physicians and Surgeons of Columbia University, and the New York State Psychiatric Institute.
Ramin Mojtabai’s work was supported in part by Grant no. MH01754 from the National Institute of Mental Health (NIMH). Mark Olfson’s work was supported in part by Grant no. MH56490 from the NIMH. The authors thank David Mechanic for his comments on an earlier version of this paper.
| NOTES |
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| TopStudy MethodsStudy ResultsDiscussion And Policy...Editor's NotesNOTES |
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- M.Gold, "Medicare+Choice: An Interim Report Card," Health Affairs (July/Aug 2001): 120–138; S.Maxwell et al., Reforming Medicare’s Benefit Package: Impact on Beneficiary Expenditure (New York: Commonwealth Fund, May 2001); and J.Stuber et al., National and Local Factors Driving Health Plan Withdrawals from Medicare+Choice: Analysis of Seven Medicare+Choice Markets (New York: Commonwealth Fund, October 2001).
- J.A.Poisal and L. Murray, "Growing Differences between Medicare Beneficiaries with and without Drug Coverage," Health Affairs (Mar/Apr 2001): 74–85.
- For a recent review of the studies linking medication coverage and medication use, see A.S. Adams et al., "The Case for a Medicare Drug Coverage Benefit: A Critical Review of the Empirical Evidence," Annual Review of Public Health 22, no. 1 (2001): 49–61. [CrossRef][Medline]There have been fewer studies linking medication coverage and health outcomes, especially in general Medicare beneficiary samples. Most notable are studies by Stephen Soumerai and his colleagues of the health impact of introduction of new caps on medication spending for New Hampshire Medicaid enrollees. S.B. Soumerai et al., "Effects of Medicaid Drug-Payment Limits on Admission to Hospitals and Nursing Homes," New England Journal of Medicine 325, no. 15 (1991): 1072–1077[Abstract]; and S.B.Soumerai et al., "Effect of Limiting Medicaid Drug Reimbursement Benefits on the Use of Psychotropic Agents and Acute Mental Health Services by Patients with Schizophrenia," New England Journal of Medicine 331, no. 10 (1994): 650–655).
[Abstract/Free Full Text] - F.T.Juster and R. Suzman, "An Overview of the Health and Retirement Study," Journal of Human Resources 30 (Supplement 1995): 7–56.
- For a detailed description of the design of the cohorts included in the HRS, see University of Michigan, Institute for Social Research, "Added Cohorts and Movement to Steady State," 4 August 1999, hrsonline. isr.umich.edu/intro/sho_uinfo.php?hfyle=steady&xtyp=2 (17 April 2003).
- L.S.Radloff, "The CES-D Scale: The Self-Reported Depression Scale for Research in the General Population," Applied Psychological Measurement 1, no. 3 (1977): 385–401; and F.J.Kohout et al., "Two Shorter Forms of the CES-D Depression Symptoms Index," Journal of Aging and Health 5, no. 2 (1993): 179–193.
[Abstract/Free Full Text] - U.S. Department of Health and Human Services, Office of the Secretary, "Annual Update of the HHS Poverty Guidelines," 9 February 2002, aspe.hhs.gov/poverty/00fedreg.htm (17 April 2003).
- Stata Statistical Software, Release 7.0 (College Station, Tex.: Stata Corporation, 2001).
- D.Federman et al., "Supplemental Insurance and Use of Effective Cardiovascular Drugs among Elderly Medicare Beneficiaries with Coronary Heart Disease," Journal of the American Medical Association 286, no. 14 (2001): 1732–1739.
[Abstract/Free Full Text] - B.Stuart et al., Designing a Medicare Drug Benefit: Whose Needs Will Be Met? (New York: Commonwealth Fund, December 2000).
- Recent proposals in Congress included provisions for low-income beneficiaries. For example, the Senate Graham-Smith bill would provide full coverage for beneficiaries with incomes below 200 percent of poverty. R.Pear, "Big Senate Vote on Medicare Drug Benefits Is for Today," New York Times, 31 July 2002.
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