Understanding Non-Adherence

The problem of non-adherence to self-administered treatment instructions is often reported in both the news media and the medical and pharmaceutical press. The World Health Organization reports that universal incomprehension rates of non-adherence are reportedly as high as 50 percent.

That such non-adherence may lead to unnecessary waste (increased healthcare costs) and poor health outcomes (reduced quality of life) are justified concerns for all healthcare professionals.

Nigel J. Crossland

But just what is meant by non-adherence and has the supportive data been subject to validation?

Adherence rates can be measured by use of patient questionnaires, performing outcome monitoring, counting returned drugs, and/or the examination of pharmacy databases/dispensed medication records; the latter being used to derive what Christopher Roebuck and his co-authors describe in their article, "Medication Adherence Leads to Lower Health Care Use and Costs Despite Increased Drug Spending," as "medication possession ratio." Nevertheless, no method other than intense supervision of each treated patient can provide an accurate depiction of whether the patient is taking their medication correctly.

While there are probably many reasons for non-adherence, including attitude and patient's behavior, there are some fairly simple areas that should not be ignored.

The clarity of the dosing instructions, deficiencies in packaging, and simple forgetfulness on the part of patients, are all elements capable of improvement. The taking of medicines in strict accordance with the prescription instructions, especially in the case of long-term illnesses, is a difficult task for even the most committed patient.

Employment of calendar-based treatment schedules showing when to take the drug and the quantity to be taken could improve adherence to more acceptable levels. This is especially true for patients taking multiple medications and where the doses are frequently changing.

Packaging of medicines has hardly changed since the first drugs were pressed into tablets, placed in screw-capped bottles, and given to patients. Now, the usage of blister packs for tablets is a welcome development. However, they may also be a cause of frustration in the case of inappropriate calendar packs—the design may not suit the dose/frequency regime for the particular patient. Unsurprisingly, inappropriate calendar packaging (e.g., two tablets per day when three are prescribed) is a common occurrence leading to confusion and mistakes.

Though pharmaceutical companies spend very large quantities of money on researching and developing their new drugs, the development of finished pharmaceutical products in their final containers together with unambiguous dosing instructions appear to be influenced by "custom and practice" rather than more intelligent design.

While there is realization of the problems caused by non-adherence in clinical practice, less has been said about the impact on clinical research. In the former, wasted financial resources and deterioration in the patients' clinical profile, with the possibility of the development of medical emergencies are obvious concerns. In the latter, the whole concept of clinical research, which is based on the gathering of evidence-based data to support the safety and efficacy of the drugs being researched, could be challenged if trial medication was not used in accordance with the dosing details of the study protocol. This has worrying implications for the running of new drug development programs where clinical trial volunteers are responsible for their own self-administered trial material.

Nigel J. Crossland

BSc, CSci, FRQA, FICR

Independent Pharmaceutical Scientist nigel.crossland@btinternet.com