REVIEW
Medication Adherence: WHO Cares?

https://doi.org/10.4065/mcp.2010.0575Get rights and content

The treatment of chronic illnesses commonly includes the long-term use of pharmacotherapy. Although these medications are effective in combating disease, their full benefits are often not realized because approximately 50% of patients do not take their medications as prescribed. Factors contributing to poor medication adherence are myriad and include those that are related to patients (eg, suboptimal health literacy and lack of involvement in the treatment decision–making process), those that are related to physicians (eg, prescription of complex drug regimens, communication barriers, ineffective communication of information about adverse effects, and provision of care by multiple physicians), and those that are related to health care systems (eg, office visit time limitations, limited access to care, and lack of health information technology). Because barriers to medication adherence are complex and varied, solutions to improve adherence must be multifactorial. To assess general aspects of medication adherence using cardiovascular disease as an example, a MEDLINE-based literature search (January 1, 1990, through March 31, 2010) was conducted using the following search terms: cardiovascular disease, health literacy, medication adherence, and pharmacotherapy. Manual sorting of the 405 retrieved articles to exclude those that did not address cardiovascular disease, medication adherence, or health literacy in the abstract yielded 127 articles for review. Additional references were obtained from citations within the retrieved articles. This review surveys the findings of the identified articles and presents various strategies and resources for improving medication adherence.

Section snippets

METHODS

We conducted a MEDLINE database literature search limited to English- and non–English-language articles published between January 1, 1990, and March 31, 2010, using the following search terms: cardiovascular disease, health literacy, medication adherence, and pharmacotherapy. Of the 405 articles retrieved, those that did not address CVD, medication adherence, or health literacy in the abstract were excluded, leaving 127 for inclusion in the review. Additional references were obtained from

GENERAL ASPECTS OF MEDICATION ADHERENCE

Medication-taking behavior is extremely complex and individual, requiring numerous multifactorial strategies to improve adherence. An enormous amount of research has resulted in the development of medications with proven efficacy and positive benefit-to-risk profiles. This millennium has seen a new and greater focus on outcomes. However, we seem to have forgotten that between the former and the latter lies medication adherence: TreatmentAdherenceOutcomes

The WHO defines adherence to

INCIDENCE OF NONADHERENCE

According to a 2003 report published by the WHO, adherence rates in developed countries average only about 50%.1 Adherence is a key factor associated with the effectiveness of all pharmacological therapies but is particularly critical for medications prescribed for chronic conditions. Of all medication-related hospitalizations that occur in the United States, between one-third and two-thirds are the result of poor medication adherence.3 A fair amount of data is available regarding medication

CAUSES OF POOR MEDICATION ADHERENCE

Poor adherence to medical treatment severely compromises patient outcomes and increases patient mortality. According to the WHO, improving adherence to medical therapy for conditions of hypertension, hyperlipidemia, and diabetes would yield very substantial health and economic benefits.1 To improve medication adherence, the multifactorial causes of decreased adherence must be understood. The WHO classifies these factors into 5 categories: socioeconomic factors, factors associated with the

STRATEGIES TO IMPROVE MEDICATION ADHERENCE

Between 2000 and 2002, the typical Medicare beneficiary saw a median of 7 physicians per year: 2 primary care physicians and 5 specialists.68 This finding highlights the need for coordinated, multifactorial strategies to improve medication adherence. However, given the enormous complexities involved in medication adherence, research on improving adherence has been challenging and generally focused on single disease states. A recent Cochrane review of 78 randomized trials found no one simple

CONCLUSION

Strong evidence shows that many patients with chronic illnesses have difficulty adhering to their recommended medication regimen. Believing that medication nonadherence is the “fault” of the patient is an uninformed and destructive model that is best abandoned. As the former Surgeon General C. Everett Koop reminded us, “Drugs don't work in patients who don't take them.”3 Thus, physicians must recognize that poor medication adherence contributes to suboptimal clinical benefits, particularly in

Acknowledgments

Editorial assistance with searching the literature, coordinating revisions, and creating figures and tables in preparation of this manuscript was provided by Melanie Leiby, PhD, and additional assistance with correspondence and permissions was provided by Barbara A. Murphy, both of inScience Communications, a Wolters Kluwer business, and funded by the Bristol-Myers Squibb/Sanofi Pharmaceutical Partnership. The authors would like to thank Joyce Pallinger, MS, MLIS, Manager, and Karly Vesely,

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    Dr Brown has served as an advisory board consultant for AstraZeneca, Bristol-Myers Squibb, and Sanofi-Aventis. Editorial assistance with searching the literature, coordinating revisions, and creating figures and tables was funded by the Bristol-Myers Squibb/Sanofi Pharmaceutical Partnership.

    An earlier version of this article appeared Online First.

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