June 1, 2023

Nonadherence to medicines: the hidden crisis for patients and healthcare systems

Prof. Nick Barber
Head of Clinical Outcomes

Nonadherence to prescribed medicines is a quiet crisis that has overshadowed healthcare for centuries and poses a significant challenge to patient health outcomes and healthcare systems. This article is the first in a series from Professor Nick Barber, Head of Clinical Outcomes at Aide Health, which looks at the magnitude of this concern, its reasons, and the possible avenues for resolution.

When Imatinib came onto the market, it was a lifesaver–literally–for patients with chronic myeloid leukaemia. Before its introduction, only 30% of patients lived five years following diagnosis; after, 90% survived. However, in general use, it was found that some patients did not progress as well as expected. Extensive biomedical and pharmacokinetic studies could not explain this; a perplexed oncologist mentioned it to an HIV specialist. “Easy,” she said, “They are not taking it.”

It seemed incredible that this could be the case, although it had been shown that some HIV patients did not take their life-saving medicines properly. A large study was set up to explore their medicine-taking behaviour, and my team interviewed the nonadherent patients to find out why.

As with nonadherence, we found a host of reasons could contribute. Nonadherence can occur in any group of medicine takers, even if their life depends on it. 

Patients not taking their medicines as the doctor advised is nothing new. Hippocrates warned physicians about it two and a half millennia ago. The behaviour was called noncompliance for many years. However, with the increased recognition of patient autonomy, it was felt there was too much of a ‘master-servant’ power dynamic inherent in the term. Instead, the terms adherent/nonadherent describe whether the patient sticks to the instructions. Before we look at the extent and consequences of nonadherence, let us consider prescribing.

The sheer volume of medicine prescribed is jaw-dropping. Half the adult population of the UK took a prescribed medicine last week. The proportion is similar in the USA and Canada – a total of 172 million users. Around a million people in the UK are prescribed ten or more medicines. The annual spend on medicines for NHS England alone is over £17 billion. It is estimated that 30%-50% of patients prescribed medicine for a long-term condition are nonadherent. Some may be taking their medicines erratically, others deliberately using a different dosing frequency, veering between periods of adherence and nonadherence, or just not taking it at all. If they are on more than one medicine, their adherence behaviour may be different with each, good with some and bad with others.

The consequences of nonadherence include a reduction in patient health and a more rapid progression of disease. Or the need to move to riskier medicines and a drain on the NHS in staff time and inefficient use of medicines. Nonadherence in just five groups of medicines costs the NHS over £1bn a year. So why don’t we sort it out? Well, it’s tricky.

Nonadherence has been seen as an intractable problem for millennia, although with the right approaches, it is tractable.

One problem is that nonadherence is more a symptom than a diagnosis; it is a behaviour with many different causes, all requiring specific interventions and support. Another problem is that it may come and go – patients may be adherent for periods and then become nonadherent, sometimes then reverting to adherence after a while. And finally, it is often, like hypertension, a silent killer. It is not visible and so it cannot be addressed.

There are several ways to understand nonadherence and to identify its cause. These allow us to design patient support and find appropriate ways to help them. In England, the New Medicines Service run by pharmacies sees a million patients a year and helps them to be more adherent. Based on fifteen years of my research, it helps capture patient problems with a medicine early on, take actions to resolve them and inform and reassure where relevant.

The key is that non-adherence is a symptom, not a diagnosis. Symptoms, such as chest pain, need a diagnosis before they can be treated – there is no point in treating it as a heart problem if it is just a chest muscle that causes the pain. Too often, people assume the cause of nonadherence and impose a solution that may be completely inappropriate. The NMS seeks to discover if nonadherence is happening and, if so, to find and resolve the cause.    

Nonadherence is generally soluble if appropriately understood. In my next article, I will explore some of the causes and explanations of non-adherence.


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