Medication adherence is defined as the degree to which the patient’s behavior corresponds with the agreed-upon recommendation from a healthcare provider. According to the World Health Organization (WHO), in developed countries only 50% of patients who have chronic diseases such as hypertension and diabetes adhere to treatment recommendations.1 Thus, nonadherence roughly accounts for 100,000 preventable deaths and $100 billion in preventable medical costs annually.2 Due to rising healthcare costs and poor health outcomes, it is important to educate healthcare professionals about barriers, measurements, and strategies to improve medication adherence.
Potential barriers to medication adherence can be categorized as either patient related or treatment related. Patient-related barriers include lack of motivation, depression, denial, cognitive impairment, substance or alcohol abuse, cultural or alternate beliefs, and low healthcare literacy. Treatment-related barriers may include complex treatment regimens, actual or concern for potential side effects, inconvenience, cost of medications, and time management. Other important barriers to adherence include poor provider−patient relationship, inadequate follow-up, suboptimal discharge planning, and treatment of an asymptomatic disease (i.e., hypertension, HIV, diabetes).2,3 Healthcare professionals who have a heightened awareness of these barriers and predictors to nonadherence can effectively target successful interventions. It is important to understand that age, race, sex, and socioeconomic status have not been consistently associated as major predictors for nonadherence; they should not be the sole basis for decisions when evaluating interventions to improve adherence.2
There are many direct and indirect methods to measure adherence. Multiple methods of measuring adherence should be used since there is no gold standard, and each method has potential advantages and disadvantages. Direct methods such as observing medication administration and drug levels are objective, but they can be impractical or impossible to do depending on the patient and the drug administered. Thus, indirect methods such as patient self-reporting, patient questionnaire, pill-counting prescription bottles, monitoring prescription refills, and measuring clinical response (i.e., heart rate, blood pressure, temperature) should be used for most patients. Many of these indirect methods are simple and easy to perform, but the disadvantages include patient distortion of the data, susceptibility of error in polypharmacy, and lack of direct correlation between the method and the clinical response. During patient interview, it is important to understand that patients often do not want to disappoint their providers and may not be forthcoming. Thus, asking questions in a nonjudgmental and non-confrontational manner makes most patients feel comfortable and facilitates an open conversation.2
Numerous interventions are available to improve medication adherence. The most common methods include patient education about medications and disease states, improved communication between healthcare professional and patient, increasing accessibility to care via more clinic hours or frequent appointments, and improving dosing schedules.2 Patient education about medications and disease states are helpful to improve health literacy, decrease concerns about medication side effects, motivate patients on self-care, and increase awareness of the harmful effects of asymptomatic diseases.1 One of ...