Medication Adherence: WHO Cares?


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. 

In its 2003 report on medication adherence,1 the World Health Organization (WHO) quoted the statement by Haynes et al that “increasing the effectiveness of adherence interventions may have a far greater impact on the health of the population than any improvement in specific medical treatments.” Among patients with chronic illness, approximately 50% do not take medications as prescribed.1,2 This poor adherence to medication leads to increased morbidity and death and is estimated to incur costs of approximately $100 billion per year.3 Thus, Hippocrates’ exhortation to the physician to “not only be prepared to do what is right himself, but also to make the patient…cooperate”4 has consistently failed for more than 2000 years. Today’s ever more complicated medical regimens make it even less likely that physicians will be able to compel compliance and more important that they partner with patients in doing what is right together.

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:Treatment → Adherence → Outcomes

The WHO defines adherence to long-term therapy as “the extent to which a person’s behavior—taking medication, following a diet, and/or executing lifestyle changes—corresponds with agreed recommendations from a health care provider.”1 Often, the terms adherence and compliance are used interchangeably. However, their connotations are somewhat different: adherence presumes the patient’s agreement with the recommendations, whereas compliance implies patient passivity. As described by Steiner and Earnest,5 both terms are problematic in describing medication-taking behavior because they “exaggerate the physician’s control over the process of taking medications.” The complex issues surrounding the taking of medication for chronic disease cannot easily be distilled into one word. Recognition of this complexity will help avoid assigning blame exclusively to the patient and assist in identifying effective solutions.

Article Highlights

  • Approximately 50% of patients do not take medications as prescribed
  • Medication adherence is not exclusively the responsibility of the patient
  • Increasing adherence may have a greater effect on health than improvements in specific medical therapy
  • Medication-taking behavior is complex and involves patient, physician, and process components
  • Identification of nonadherence is challenging and requires specific interviewing skills
  • Solutions include encouraging a “blame-free” environment, opting for less frequent dosing, improving patient education, assessing health literacy, and paying attention to rational nonadherence
  • Many helpful Web-based resources are available

This article breaks down the issues with medication adherence into three categories: patients, physicians, and health care systems. These three categories overlap in many ways which means a solution needs to touch at least two of the categories to be an effective one. These three categories have a causation relationship. Ineffective medication adherence rooted in a physician’s actions causes lower pharmaceutical literacy amongst health care systems and patients. Another key takeaway is the difficulty of identifying non-adherence amongst patients. Building a better sense of trust between patient and physician as well as between patient and health care systems will result in better overall health care.


  1. I really liked the mental model you created in your analysis and think it’s worth noting in our findings. In that, there are 3 parts to medication adherence. I specifically liked the idea that trust and communication are key to improving the system. I think with more communication, the trust will follow.


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