What exactly do compliance and adherence mean?
Compliance suggests a one-way relationship, whereby the doctor states the medical regimen and the patient is expected to comply.1 On the other hand, adherence is the “active, voluntary, and collaborative involvement of the patient in a mutually acceptable course of behaviour to produce a therapeutic result”. Here, the patient is a partner in healthcare decision making, and both patient and healthcare professional agree on treatment goals and the medical regimen.1,2
Adherence to therapy is very important for the management of long-term diseases such as heart disease and diabetes.3 The World Health Organization defines adherence to long-term therapy as “the extent to which a person’s behaviour—taking medication, following a diet, and/or executing lifestyle changes, corresponds with agreed recommendations from a healthcare provider”.4
Medication adherence can be measured using direct and indirect methods2:
Examples of direct methods: Healthcare worker watching the patient take every dose of the medication, measurement of medication levels in the blood.
Examples of indirect methods: Surveys, diaries, patient self-report, pharmacy refill rates, pill counting, monitoring for clinical response, and electronic data.
Prevalence of adherence to medications
In developed countries, adherence among patients with long-term diseases such as high blood pressure (BP) averaged at only 50%, and this figure is assumed to be worse in developing countries.4
In Malaysia, good adherence to high BP medication was found to be 53.4%.5
In the United States, 65.4% of patients with type 2 diabetes achieved adherence rates of 80% or better in their first year of medication therapy.6
A study showed that 2 years after hospitalization for acute coronary syndrome (eg, heart attack or unexpected chest pain), only around 40% of patients continued taking statins (cholesterol-lowering medications).2
Non-adherence can manifest in many ways, eg, not filling a new prescription or taking less than the dose recommended by the doctor. It has been found that 20–22% of new prescriptions for long-term conditions such as high BP, diabetes and high cholesterol were not filled.3
How are long-term diseases related to adherence and compliance?
Poor adherence to recognized standards of care is the main reason behind the development of diabetes complications.4 The biggest barrier to effective insulin therapy is compliance.7
Similarly, the main cause of failure to control high blood pressure (BP) is poor adherence. It is estimated that poor adherence contributes to poor BP control in over two-thirds of people with high BP.4 Medication non-compliance can result in BP not reaching target despite being prescribed up to three BP medications.8
Rates of uncontrolled high BP, diabetes and high cholesterol in Malaysia
- High BP: Only 35% of patients achieved BP control while on treatment.8
- Diabetes: In government health clinics, only 23.8% of patients with type 2 diabetes achieved the national HbA1c target.9
- High cholesterol: Among patients with type 2 diabetes, only 28.5% and 37.8% achieved target total cholesterol and low-density lipoprotein (“bad”) cholesterol, respectively.9
Why don’t people take their medications as directed?
- The medication is for a disease for which they do not experience any symptoms, eg, high blood pressure or high cholesterol3
- Lack of understanding of the disease3
- Forgetfulness10
- Misunderstanding or confusion on instructions, eg, how and when to take11
- Not convinced that the medication is effective10
- Unsure if the medication is working10
- Presence of side effects10,11
- Fear (such as of medication dependence or side effects)11
- Duration or complexity of treatment11
- Having to take the medication multiple times a day3
- Difficulty in taking medications (eg, confused about use of injections or inhalers)10
- Poor relationship between the patient and the healthcare professional3
- Missed appointments with the doctor3
- Medication cost (too expensive)11