Original research
Association of Chronic Obstructive Pulmonary Disease Maintenance Medication Adherence With All-Cause Hospitalization and Spending in a Medicare Population

https://doi.org/10.1016/j.amjopharm.2012.04.002Get rights and content

Abstract

Background

Although maintenance medications are a cornerstone of chronic obstructive pulmonary disease (COPD) management, adherence remains suboptimal. Poor medication adherence is implicated in poor outcomes with other chronic conditions; however, little is understood regarding links between adherence and outcomes in COPD patients.

Objective

This study investigates the association of COPD maintenance medication adherence with hospitalization and health care spending.

Methods

Using the 2006 to 2007 Chronic Condition Warehouse administrative data, this retrospective cross-sectional study included 33,816 Medicare beneficiaries diagnosed with COPD who received at least 2 prescriptions for ≥1 COPD maintenance medications. After a 6-month baseline period (January 1, 2006 to June 30, 2006), beneficiaries were followed through to December 31, 2007 or death. Two medication adherence measures were assessed: medication continuity and proportion of days covered (PDC). PDC values ranged from 0 to 1 and were calculated as the number of days with any COPD maintenance medication divided by duration of therapy with these agents. The association of adherence with all-cause hospital events and Medicare spending were estimated using negative binomial and γ generalized linear models, respectively, adjusting for sociodemographics, Social Security disability insurance status, low-income subsidy status, comorbidities, and proxy measures of disease severity.

Results

Improved adherence using both measures was significantly associated with reduced rate of all-cause hospitalization and lower Medicare spending. Patients who continued with their medications had lower hospitalization rates (relative rate [RR] = 0.88) and lower Medicare spending (–$3764), compared with patients who discontinued medications. Similarly, patients with PDC ≥0.80 exhibited lower hospitalization rates (RR = 0.90) and decreased spending (–$2185), compared with patients with PDC <0.80.

Conclusions

COPD patients with higher adherence to prescribed regimens experienced fewer hospitalizations and lower Medicare costs than those who exhibited lower adherence behaviors. Findings suggested the clinical and economic importance of medication adherence in the management of COPD patients in the Medicare population.

Introduction

Chronic obstructive pulmonary disease (COPD) affects >1 in 15 (24 million) adults in the United States,1, 2 surpassing stroke as the third leading cause of death.3 COPD also affects 12% of elderly adults and disabled Medicare beneficiaries,4 and is frequently associated with comorbid conditions and increased disease severity.5, 6, 7 In 2007, the costs of COPD exceeded $42 billion, with $29.5 billion attributable to direct health care expenditures and $8 billion to mortality.8

Pharmacotherapy is a cornerstone of COPD management. Maintenance medications are effective in controlling symptoms, maintaining lung function, and preventing acute COPD exacerbations.1, 9 The regular use of bronchodilators, including long-acting β2-agonists (LABAs), anticholinergics, and methylxanthines, and LABAs and inhaled corticosteroids are effective in maintaining the health status of COPD patients.1, 9

Research suggested half of COPD patients failed to use any maintenance medications.10, 11 To maximize treatment outcomes, maintenance medications should be used on a long-term regular basis, and should not be discontinued.1 Although COPD medication adherence approached 80% in clinical trials,12 in clinical practice, observed adherence levels ranged from 10% to 60%13, 14, 15, 16, 17 and only half of patients continually used their prescribed medications for a year.10, 17, 18

Despite the clinical and economic implications associated with suboptimal COPD maintenance medication management, few studies examined the influence of medication adherence on hospitalization and costs. Although research suggested increased COPD maintenance medication use reduced hospitalization, emergency department visits, and associated costs,6, 11, 16, 19, 20, 21, 22 limitations remain and include: data on comparative cost-effectiveness of specific regimens (ie, head-to-head trials); need for studies on medication adherence; reliance on simulation techniques using hypothetical patients and imputed costs; and failure to target Medicare beneficiaries. Finally, despite growing recognition of the deleterious effects of medication discontinuation in individuals with cardiovascular disease,7 myocardial infarction,23, 24 and rheumatoid arthritis,25 discontinuation of medication remains unclear in COPD patients.

Using a nationally representative sample of Medicare beneficiaries, the objectives of this study were to: (1) estimate the prevalence of COPD maintenance medication continuity and adherence measured by proportion of days covered (PDC); and (2) examine the association of COPD maintenance medication continuity and adherence on hospitalization and Medicare spending.

Section snippets

Study Design and Data

This study was a retrospective cross-sectional study using a 5% random sample of Medicare claims records from the 2006 to 2007 Chronic Condition Warehouse (CCW). These 2 years were used to assess medication adherence among Medicare Part D enrollees during the first 2 years of their enrollment in the program. The CCW data included detailed administrative data for all Medicare Part A (inpatient), B (outpatient), and D (prescription drug) services.26 The first 6 months (January 1, 2006 to June 30,

Results

A sample of 33,816 beneficiaries with COPD who had at least 2 Part D prescription claims for COPD maintenance medications during the 18-month follow up was obtained. This sample was predominantly female (64.9%), white (87.3%), with a mean age of 71 years, and LIS eligible (63.7%) (Table I). Hypertension was the most common comorbid condition (69.9%), followed by ischemic heart disease (51.2%). Nearly 1 in 3 (31.8%) beneficiaries experienced a hospitalization at baseline (January 1, 2006 to June

Discussion

Results of this study demonstrated that increased measures of adherence to maintenance medications of proven benefit in COPD appeared to be significantly associated with reduced hospitalization rates and total Medicare spending. Both lack of interruption in drug dispensing and higher adherence were associated with better clinical outcomes. Increased adherence also resulted in significant decreases in total, Part A, and Part B Medicare spending. Although Part D prescription drug spending was

Conclusions

Findings from this study indicated that COPD maintenance medication use over an extended period was associated with better clinical and economic outcomes. Improving adherence might provide significant cost-savings—for the patient, who might incur copayments, and for the Medicare program. The results highlighted the need for interventions that improve the adherence of essential COPD maintenance medications to reduce exacerbations and associated costs.

Conflicts of Interests

This study was funded by GlaxoSmithKline. Dr. Dalal and Ms. Bryant-Comstock are employees of GlaxoSmithKline and own company stock. The remaining authors received financial support from GlaxoSmithKline to conduct the study. The authors have indicated that they have no other conflicts of interest regarding the content of this article.

Acknowledgments

This study was funded by GlaxoSmithKline. Dr. Simoni-Wastila was the guarantor of the article, taking responsibility for the integrity of the work as a whole, from inception to published article. Drs. Simoni-Wastila, Stuart, Zuckerman, and Dalal worked on the study concept and design. Dr. Simoni-Wastila acquired the data. Drs. Simoni-Wastila, Stuart, Zuckerman, Wei, Qian, Mr. Shaffer, and Dr. Dalal analyzed and interpreted the data. All of the authors drafted and revised the article. Drs. Wei,

References (43)

  • B. Stuart et al.

    Medication Use by Age and Disabled Medicare Beneficiaries Across the Spectrum of Morbidity–A ChartbookThe Peter Lamy Center on Drug Therapy and Aging

    (2007)
  • A.A. Dalal et al.

    COPD-related healthcare utilization and costs after discharge from a hospitalization or emergency department visit on a regimen of fluticasone propionate-salmeterol combination versus other maintenance therapies

    Am J Manag Care

    (2011)
  • L.A. Garcia Rodriguez et al.

    Increased risk of stroke after discontinuation of acetylsalicylic acid: a UK primary care study

    Neurology

    (2011)
  • Morbidity & Mortality: 2009 Chart Book on Cardiovascular, Lung, and Blood Diseases

  • American Thoracic Society and European Respiratory Society standards for the diagnosis and management of patients with COPD

  • J. Vestbo et al.

    Adherence to inhaled therapy, mortality and hospital admission in COPD

    Thorax

    (2009)
  • M.S. Charles et al.

    Adherence to controller therapy for chronic obstructive pulmonary disease: a review

    Curr Med Res Opin

    (2010)
  • C.S. Rand

    Patient adherence with COPD therapy

    Eur Respir Rev

    (2005)
  • R.D. Restrepo et al.

    Medication adherence issues in patients treated for COPD

    Int J Chron Obstruct Pulmon Dis

    (2008)
  • J.A. Cramer et al.

    Treatment persistence and compliance with medications for chronic obstructive pulmonary disease

    Can Respir J

    (2007)
  • L. Blais et al.

    Inhaled corticosteroids in COPD: determinants of use and trends in patient persistence with treatment

    Can Respir J

    (2004)
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