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The American Journal of Managed Care December 2013
Implementing Effective Care Management in the Patient-Centered Medical Home
Catherine A. Taliani, BS; Patricia L. Bricker, MBA; Alan M. Adelman, MD, MS; Peter F. Cronholm, MD, MSCE, FAAFP; and Robert A. Gabbay, MD, PhD
Cost Utility of Hub-and-Spoke Telestroke Networks From Societal Perspective
Bart M. Demaerschalk, MD, MSc; Jeffrey A. Switzer, DO; Jipan Xie, MD, PhD; Liangyi Fan, BA; Kathleen F. Villa, MS; and Eric Q. Wu, PhD
Generic Initiation and Antidepressant Therapy Adherence Under Medicare Part D
Yuhua Bao, PhD; Andrew M. Ryan, PhD; Huibo Shao, MS; Harold Alan Pincus, MD; and Julie M. Donohue, PhD
Economics of Genomic Testing for Women With Breast Cancer
Robert D. Lieberthal, PhD
Impact of Electronic Prescribing on Medication Use in Ambulatory Care
Ashley R. Bergeron, MPH; Jennifer R. Webb, MA; Marina Serper, MD; Alex D. Federman, MD, MPH; William H. Shrank, MD, MSHS; Allison L. Russell, BA; and Michael S. Wolf, PhD, MPH
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Medication Utilization and Adherence in a Health Savings Account-Eligible Plan
Paul Fronstin, PhD; Martin-J. Sepulveda, MD; and M. Christopher Roebuck, PhD, MBA
Collection of Data on Race/Ethnicity and Language Proficiency of Providers
David R. Nerenz, PhD; Rita CarreĆ³n, BS; and German Veselovskiy, MS
Dietary Diversity Predicts Type of Medical Expenditure in Elders
Yuan-Ting Lo, PhD; Mark L. Wahlqvist, MD; Yu-Hung Chang, PhD; Senyeong Kao, PhD; and Meei-Shyuan Lee, DPH

Medication Utilization and Adherence in a Health Savings Account-Eligible Plan

Paul Fronstin, PhD; Martin-J. Sepulveda, MD; and M. Christopher Roebuck, PhD, MBA
A consumer-directed health plan with a health savings account was associated with reduced adherence for 4 of 5 conditions.
Objectives: To evaluate the impact of a consumerdirected health plan with a health savings account (CDHP-HSA) on utilization of and adherence to medications among individuals with chronic disease.

Study Design: Pre-post comparison study with matched control group (difference-in-differences analysis).

Methods: Data on workers and dependents with 1 or more of 5 chronic conditions—hypertension, dyslipidemia, diabetes, asthma/chronic obstructive pulmonary disease (COPD), and depression—were obtained from an employer that fully replaced its  preferred provider organizations (PPOs) with a CDHP-HSA in 2007. A control group of participants from an employer that maintained its PPO throughout the 3-year study period (2006-2008) was created by matching on preperiod (2006) individual characteristics. Difference-in-differences estimates of the impact of the CDHP-HSA were derived by chronic condition for number of prescriptions,  proportion of days covered (PDC), and an indicator for a PDC of 0.80 or higher.

Results: During the first year after implementation, enrollees with hypertension, dyslipidemia, and diabetes had significantly less medication utilization (by 1-2 prescriptions) and lower adherence rates (by 0.05-0.09 in PDC; 0.04-0.13 in the proportion adherent). These reductions abated, yet remained, after 2 years among hypertension and dyslipidemia patients. The PDC was significantly lower in patients with depression by 0.07 and 0.05 after 1 and 2 years under the new plan, respectively. No statistically significant impacts were detected on enrollees with asthma/COPD.

Conclusions: A CDHP-HSA full replacement was associated with reduced adherence for 4 of 5 conditions. If this reduced adherence is sustained, it could adversely impact productivity and medical costs.

Am J Manag Care. 2013;19(12):e400-e407
We examined the impact of plan design on medication utilization and adherence among individuals with chronic disease employed by a company that adopted a consumer-directed health plan (CDHP) with a health savings account (HSA) for all workers.
  • During the first year after CDHP-HSA implementation, enrollees with hypertension, dyslipidemia, and diabetes had significantly less medication utilization and lower adherence rates. These reductions abated, yet remained, after 2 years among hypertension and dyslipidemia patients.

  • Adherence was significantly lower in patients with depression after 2 years.

  • There were no statistically significant impacts on enrollees with asthma/chronic obstructive pulmonary disease.
Medication is important in the management of noncommunicable chronic diseases, which affect nearly one-half of adults and cause approximately 70% of deaths in the United States.1 Prescription drugs accounted for 12% of healthcare spending in 2012, more than double the level of 30 years ago (5%).2 In general, this shift toward greater use of pharmacotherapy has provided net societal benefits.3 For example, medical cost offsets in Medicare A and B have been documented as a result of adding drug coverage under Medicare Part D.4 Prior work has found that medication adherence produced substantial savings as a result of reductions in hospitalization and emergency department use, and it is thus a matter of great importance to policy makers, insurance plan sponsors, physicians, and patients.5

Despite clinical and economic benefits, only about half of patients take medications for their chronic conditions as recommended by their physicians.6 Moreover, as much as one-third of initial prescriptions go unfilled.7,8 For example, studies have found that more than 25% of patients with coronary artery disease discontinued drug therapy within 6 months of initiation,9 and adherence among patients receiving statins fell from nearly 80% within the first 3 months of treatment to only 25% after 5 years.10 Overall, adherence rates across a number of therapeutic classes have been reported at between 28% and 66% after 6 months, and 18% to 54% after 1 year.11 Nonadherence has been estimated to cost the US healthcare system between $100 billion and $289 billion,12 and has spawned new plan designs such as value-based insurance design to address this challenge.13 Public efforts to raise awareness of  the adverse effects of nonadherence have also been initiated, such as the “Script Your Future” campaign of the National Consumers League.14

Medication adherence is known to be affected by out-of-pocket cost to patients.6 For this reason, it is important to understand medication adherence in populations enrolled in relatively new types of health plans that combine potentially high out-of-pocket costs as a result of high deductibles with tax-preferred savings accounts (consumer-directed health plans; CDHPs). First introduced in 2001 with health reimbursement arrangements (HRAs), savings account–based high-deductible plans were extended by the Medicare Modernization Act of 2003, which authorized high-deductible health plans with health savings accounts (HSAs). Both types of CDHPs have grown steadily over the past decade such that by 2011, 23% of employers had offered either an HRA- or HSA-eligible CDHP—covering about 21 million individuals or about 12% of the privately insured market.15,16 About 13.5 million individuals were in a CDHP with an HSA account by January 2012.17 Importantly, as of 2012, 8% of large employers had completely replaced their healthcare coverage with only a CDHP.18

Much of the existing literature on the impact of CDHPs on use of health services and costs focuses on HRAs. These plans have been in existence longer, and data on HSAs are not as readily available. Moreover, several studies were limited to examining the impact of CDHP on healthcare spending.19-21 Peer-reviewed articles about the impact on prescription drug use of adopting a CDHP have largely concentrated on the number of prescription drug fills, generic and brand use, and mail order use by CDHP enrollees compared  ith non-CDHP enrollees.22-27 Sometimes, populations with specific diseases were examined.

We identified only 2 studies that report on the impact of a CDHP on medication adherence. An early study examining 1 year of data after the adoption of an HRA found that 7% of those enrolled in the highest deductible CDHP and taking medication to treat hypertension in late 2003 were no longer persistent with therapy in 2004, though adherence was unchanged among individuals who continued to take medications after moving to the CDHP.28 A more recent study using data from 2005 and 2006 found that after enrolling in a CDHP (both HRAs and HSAs were examined), individuals were less likely to refill prescriptions for cardiac conditions and elevated cholesterol. The CDHP members with asthma, cardiac conditions, and high cholesterol also had reduced medication adherence and persistence with medications.29

Given that CDHPs alter out-of-pocket cost for prescription drugs by subjecting them to the high deductible, one might expect this plan design to impact medication adherence. The magnitude and duration of the effect are unclear, however, because an individual with a CDHP plan may have money in an HRA or HSA, and individuals’ use of these funds will influence out-of-pocket costs for prescription drugs over  ime. The account type, employer contribution level, account ownership, and rollover provisions will further complicate the issue.

This study evaluates the impact of adopting an HSA-eligible CDHP (CDHP-HSA) on medication adherence for individuals with chronic disease. Data come from a large manufacturer that replaced all of its existing health insurance options with a CDHP-HSA. Pre-post changes in medication adherence were derived from pharmacy claims and were compared with changes in adherence in a matched control group of a second employer that did not alter its healthcare coverage.


CDHP Group

On January 1, 2007, a large Midwestern manufacturer fully replaced its existing preferred provider organization (PPO) health insurance plans with CDHP plans with an HSA. All active employees and their dependents were transitioned to the new plan and were given a choice between 2 annual deductible levels: $1250 individual/$2150 family or $2150 individual/$4300 family. The employer contributed the same amount to the HSA regardless of deductible level, though contributions were higher for those with family coverage.

To evaluate the impact of this plan design change on medication utilization and adherence, integrated pharmacy and medical administrative claims data, as well as enrollment information, were used. A control group was constructed, as described below, using data on another larger employer’s workers, who were consistently covered under traditional PPO plans. To be included in the analysis, subjects were required to be continuously eligible for benefits during the 3-year study period (January 1, 2006, through December 31, 2008) and aged at least 18 years as of January 1, 2006, but less than 65 years as of December 31, 2008. Furthermore, individuals must have had 1 or more of 5 chronic conditions: hypertension, dyslipidemia, diabetes, asthma/chronic obstructive pulmonary disease (COPD), and depression. These conditions were chosen because they are highly prevalent, costly, and routinely managed with pharmacotherapy.30 Patients were defined as having a condition if they had at least 1 inpatient or 2 outpatient claims with an International Classification of Diseases, Clinical Modification Ninth Revision diagnosis code for the illness and at least 1 prescription drug fill indicated for the condition in 2006. Table 1 shows the classifications utilized. These inclusion criteria were met by 1023 CDHP-HSA enrollees with hypertension, 1184 with dyslipidemia, 314 with diabetes, 169 with asthma/COPD, and 430 with depression. 

Control Group

A control group was created using data from another larger national employer. We attempted to pair each member of the CDHP group with 1 individual from the comparison pool using coarsened exact matching, a technique that reduces dimensionality through the binning of variables used in the  match process.31 Specifically, for each chronic condition, subjects were exactly matched on baseline (2006) values of the following variables with specified cut points (in parentheses): sex; age (25, 35, 45, and 55 years); geographic region; Charlson Comorbidity Index score (0, 1, 2, 3)32,33; proportion of days covered (PDC; 0.2, 0.4, 0.6, 0.8); and an indicator for whether or not the first prescription occurred after April 1, 2006 (ie, a proxy measure for a new user because the patient apparently did not have medication on hand at the beginning of 2006). Using these parameters, matches were obtained for a majority (68%-92%) of study subjects. Final sample sizes for the CDHP and control groups were 937 with hypertension, 1057 with dyslipidemia, 226 with diabetes, 115 with asthma/COPD, and 347 with depression.

Dependent Variables

Three annual measures of medication utilization and adherence were used as dependent variables: (1) the number of 30-day adjusted prescriptions filled for the condition; (2) the PDC for the condition, which represents the fraction of days in the period that the patient had at least 1 drug for the condition on hand; and 3) a flag indicating a PDC of 0.80 or higher, a commonly used threshold for adherence.5 Proportion of days covered is now used, for example, by the Centers for Medicare & Medicaid Services as a quality measure component of the Star Ratings calculation for stand-alone prescription drug plans, as well as Medicare Advantage Plans.34

Statistical Analysis

In addition to univariate and bivariate analyses, multivariate models were estimated using a difference-in-differences design. Specifically, for each of the 3 dependent measures, a model was specified, which included the following as independent variables: age, sex, region, Charlson Comorbidity Index score, year dummies, a CDHP group indicator, and a flag for whether or not the individual was the policy holder. Additionally, 2 interaction terms for CDHP group in 2007 and CDHP group in 2008 were entered into the equations to identify the CDHP effects in the post implementation period. Given its count properties, number of prescriptions was specified using a negative binomial model. The PDC model was estimated using ordinary least squares, and adherent was cast as a probit. In all models, standard errors were clustered by individual. Finally, marginal effect estimates of the CDHP impact in 2007 and 2008 were derived, taken at the mean of the regressors, using the delta method. All analyses were conducted using Stata release MP 12.1.35


Characteristics of the CDHP and control groups for each of the 5 chronic diseases are shown in Table 2. The average age was 52 years for individuals with hypertension, dyslipidemia, and diabetes, and 43 to 44 years for individuals with asthma/COPD and individuals with depression. Those with hypertension, dyslipidemia, and diabetes were more likely to be male and the policy holder compared with members with asthma/COPD and depression, who were more likely to be female and a dependent. Members were overwhelmingly from the Midwest. As reflected in the Charlson Comorbidity Index score, diabetic patients were the least healthy, followed by asthma/COPD patients.

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