The Medication Use Continuum

 

 

 

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According to the World Health Organization (WHO), adherence is generally defined as the extent to which a person’s behavior—taking medication, following a diet, or making healthy lifestyle changes—corresponds with agreed-upon recommendations from a healthcare provider. 

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Medication adherence is generally defined as the patient’s conformance with the provider’s recommendation with respect to timing, dosage, and frequency of medication taken during the prescribed length of time. 

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Patients are generally considered adherent to their medication if their proportion of days covered (PDC) is equal to or greater than 0.8 (or 80%). Eighty percent is the goal for patients on most classes of chronic medications (antiretrovirals for HIV/AIDS and some cancer oral therapies have an approximately 0.95, or 95%, threshold).

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A. Incidence of medication nonadherence

• Approximately 187 million Americans take one or more prescription drugs, and up to 50% of them do not take their medications as prescribed.

• A study in the Annals of Internal Medicine found that more than 31% of all first-time drug prescriptions were not filled within nine months.

• For disease conditions where there are minimal to no symptoms, such as high cholesterol and high blood pressure, over 50% of people stop taking their medications after 12 months (and sometimes much sooner).

• One out of eight heart attack patients stops taking lifesaving drugs after just one month.

• One out of two prescriptions are not taken as directed. In 2005, over 3.8 billion prescriptions were dispensed, but 1.9 billion prescriptions were not taken as directed. 

 
B. The medication use continuum

Before examining the most common causes and reasons for medication nonadherence, it is essential to understand the medication use continuum. When a patient has been diagnosed with a condition, prescriptions are ordered via either a paper prescription or e-prescribing. From there, the prescription is filled in the pharmacy, the patient is consulted about the prescription, and then the patient takes it home for consumption.

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If the prescription has refills (or if it is a medication for chronic use), the patient will order the refills in time to prevent a break in use.  This is called the medication use continuum. At each point in the continuum, medication adherence can break down. According  to  the  American  Heart  Association,  in  patients with cardiovascular disease, if 100 patients receive a prescription from their provider, about 12 of them will not fill it; 88 will go to the pharmacy  to get their prescription filled, but of the 88, about 12 will decide not   to take it. Primary nonadherence occurs when a patient does not get  the prescription filled or does not take it upon receiving it from the pharmacy. Of the patients who end up taking their prescriptions, within six months, about another 29 stop or reduce the frequency of use (without their provider’s permission). When a patient starts the therapy but stops or reduces the dosage frequency, this is known as secondary nonadherence. So, of the 100 patients who received prescriptions, about half of them are not taking the medication as prescribed within six months. 

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C.  Most common causes of medication nonadherence along the medication use continuum

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Addressing every barrier possible in each patient would not be realistic. Trying to find one solution that will address adherence in all patients rarely works.

The Most Common Medication Adherence Barriers Associated with Primary and Secondary Nonadherence:

Research on medication adherence barriers has indicated there are two sets of barriers that generally impact the majority of patients taking medications. One set generally leads to primary nonadherence, and the second set leads to secondary nonadherence. 

Primary Non-Adherence: The set of barriers that increase primary non adherence in many patients—B.R.E.A.M: Beliefs and Motivation, Relationships, Experiences, Affordability, and Medication Related Challenges

Secondary Non-Adherence: The set of barriers that increase secondary non adherence in most patients-F.R.A.M.E: Forgetfulness, Relationships, Affordability, Motivation, Medication Related Challenges, and Experiences

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D.  Impact and Consequences When Medication Adherence Is Not Optimized:

Medication nonadherence impacts these major constituents—patients, providers, the healthcare system, health plans and healthcare insurers, employers, and pharmaceutical manufacturers. Patients have a reduced quality of life, increased mortality and morbidity, more complications, and higher long-term health costs. In the new value-based healthcare system, providers are at higher risk of revenue loss and penalties for quality measures, many of which are directly or indirectly linked to medication adherence. The entire healthcare system is burdened by increased healthcare costs, increased hospitalization rates, and potential penalties for poor quality outcomes due to medication nonadherence. Employers lose productive employees and productivity due to employees missing work. Health plans, insurers, and pharmaceutical companies forego potential revenues worth millions (even billions) of dollars, especially for medications used in chronic conditions. Overall, the consequences of medication nonadherence on the healthcare system include increased hospitalizations and nursing home admits, decrease in population health, increased mortality, increased total healthcare costs, and many other economic impacts.

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E.  Improving Adherence with Medication Regimens Can Make a Positive Difference

• In the HOPE (Heart Outcomes Prevention Evaluation) Study, patients at high risk of cardiovascular events who were adherent to the study medications had significantly less episodes of myocardial infarction, stroke, and cardiovascular death compared to patients not on the medications, resulting in improved morbidity and mortality.

• Diabetic patients with coronary heart disease in the Scandinavian Simvastatin Survival Study (4S) who were adherent to their cholesterol lowering Simvastatin medication showed improved prognosis compared to non-adherent patients.

• In a 2005-2008 CVS Caremark integrated pharmacy study, which looked at the impact of medication adherence in chronic vascular disease on health services spending for patients age 65 and older, the annual per person healthcare savings totaled $7,893 for congestive heart failure, $5,824 for hypertension, $5,170 for diabetes, and $1,847 for dyslipidemia. The average benefit-cost ratios from adherence for this group were 8.6:1 for congestive heart failure, 13.5:1 for hypertension, 8.6:1 for diabetes, and 3.8:1 for dyslipidemia.

• In the preventing myocardial infarction (MI) and stroke with a simplified bundle of cardioprotective medications study, patients who were adherent to their statin and an ACEI/ARB medications showed a reduction the risk by up to 60% in hospitalization for MI and stroke.

• The Vitality study “Impact of Medication Adherence on Hospitalization Risk and Healthcare Cost,” found that for a number of chronic medical conditions (diabetes, hypercholesterolemia, hypertension, and heart failure) as adherence improved, hospitalization decreased.

 

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