Dr Andrew Rut, September 2021
Medication adherence is said to be one of the greatest barriers to improving health outcomes, yet adherence levels for chronic medications across therapeutic indications runs at around 50%1,2. In 2001 the WHO published the Adherence to Long-term Therapies: Policy for Action which states “In developed countries, such as the United States, only 51% of the patients treated for hypertension adhere to the prescribed treatment”3. Little has changed in the following 20 years. Data on patients with depression reveal that between 40% and 70% adhere to antidepressant therapies4. In the treatment of HIV and AIDS, adherence to antiretroviral agents varies between 37% and 83% depending on the drug under study and the demographic characteristics of patient populations. This represents a tremendous challenge to population health efforts where success is determined primarily by adherence to long-term therapies.
Campbell et al recently published a paper on the prescription patterns, adherence, and associated costs of metformin prescription in Canada5. The study, which used real-world prescription data over a four-year period (April 2012 to March 2017), found that non-adherence and discontinuation of metformin was very common, with a considerable drop-off within in the first 3 months and only 54% of individuals who started on metformin remaining on it after 1 year.
While it is interesting to see evidence measuring the extent of the non-adherence issue for metformin, is it really any surprise? The gastrointestinal side effects are well documented, (abdominal discomfort, diarrhoea, and nausea etc)6.
The problem is all too often healthcare professionals and pharmaceutical companies do not recognise the impact of such events on patients. They may be termed medically ‘non-serious’ yet such symptoms can have a profound effect on quality of life and are likely to impact adherence significantly.
As one patient puts it: “A drug that causes acute diarrhoea is not a ‘side effect’ but a real-life altering problem. Having to run to the toilet with less than a minute warning makes [activities] not possible unless one opts for wearing [diapers]”.5
A study into the link between adverse events and non-adherence to anti-hypertensive medicines found that almost a third of patients in the study reported poor adherence, with a fifth of participants believing their symptoms were caused by their medications7. Tiredness, muscle pain, and poor sleep were particularly associated with poor adherence. On a more serious note, treating people who do not require treatment can result in a negative benefit-risk for the individual. For instance, there is evidence to suggest that treating mild hypertension prevents fewer cardiovascular events than the serious syncopal events caused as a result of treatment. Syncope particularly in elderly patients is associated with morbidity and mortality8,9.
Knowing which sub-groups to treat, informing patients better, and enabling them to communicate their adverse experiences quickly maximises therapy benefit to the individual, optimises adherence, and reduces overall healthcare burden to society.
Our contract with patients
“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”.4
Increasing medication adherence has been a fundamental goal for healthcare systems for decades. Tackling the interplay between the patient, their disease, and the medications through effective communication and guidance is the only route to long-term success.
Counselling patients at first prescription, and at regular ongoing intervals, to ensure they understand the possible adverse that they may experience and how these can be managed is key.
It is all about support, not blame. Let’s imagine a system that values reporting of problems, makes it easy to provide those reports and takes action or communicates promptly with the patient. Only then can we help patients manage their medication and ultimately their health outcomes. The outcome will be positive for the individual and for society.
- Medication Adherence: The Elephant in the Room
- Medication Adherence: WHO Cares?
- Adherence to Long-term Therapies: Policy for Action (2001)
- Adherence to Long-term Therapies: Evidence for Action (2003)
- First-line pharmacotherapy for incident type 2 diabetes: Prescription patterns, adherence and associated costs
- Understanding and overcoming metformin gastrointestinal intolerance
- Adverse effects and non-adherence to antihypertensive medications in University of Gondar Comprehensive Specialized Hospital
- Benefits and Harms of Antihypertensive Treatment in Low-Risk Patients With Mild Hypertension
- Interventions for helping patients to follow prescriptions for medications