Medication adherence: WHO cares?

Abstract

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.

FIGURE 1.

Persistence with secondary prevention medication in the 24 months after ischemic stroke in Sweden. Persistent use of secondary preventive drugs declines rapidly during the first 2 years after stroke. From Stroke, with permission.

FIGURE 2.

Percentage of patients adherent (proportion of days covered ≥80%) to antihypertensive (AH) and lipid-lowering (LL) therapy, by prescription burden. From Am J Health Syst Pharm, with permission. ©2009, American Society of Health System Pharmacists, Inc. All rights reserved.

FIGURE 3.

Adherence to medication according to frequency of doses. Vertical lines represent 1 SD on either side of the mean rate of adherence (horizontal bars). From N Engl J Med, with permission from the Massachusetts Medical Society. All rights reserved.