By Mary Gabb ([email protected])

As we reported in last month’s HOC, the past few years have witnessed a surge of interest in the role of adherence in health economics research, highlighted by a recent report from the National Council on Patient Information and Education (NCPIE) in the United States, which revealed the high rates of non-adherence.

So, how is the issue of non-adherence being used in health economics research? JoAnne LaFleur, Research Assistant Professor at the Pharmacotherapy Outcomes Research Center, University of Utah College of Pharmacy (Salt Lake City, UT, USA) and a member of the ISPOR special interest group on adherence/compliance, says that when adherence is factored into cost-outcomes studies, it’s probably not done well and this has important public health policy implications.

She cites a recent example in which two cost-effectiveness studies in H pylori eradication (H pylori is an infectious agent thought to be associated with peptic ulcer) had made assumptions about poor patient adherence to the less costly regimen that resulted in poor cost-effectiveness outcomes with that regimen, and favourable cost-effectiveness outcomes for the more expensive regimens. As she explains, “those cost-effectiveness studies had been responsible for spurring treatment guidelines favouring the more expensive regimens. However, using a real-world dataset, the authors of this paper showed that the assumptions about patient adherence did not translate into diminished effectiveness for the less costly regimen, and in fact, previous decisions based on those cost-effectiveness studies were flawed.”

However, not all news is dire when health economics research is translated into public health policy. For example, a team at the University of Michigan, USA, has developed the concept of ‘benefit-based copay(ment)’ (lead author, Mark Fendrick, MD, Professor in the Department of Internal Medicine and the Department of Health Management and Policy and Co-Director of the Consortium for Health Outcomes Innovation and Cost Effectiveness Studies (CHOICES). David B. Nash, MD, MBA, Chairman of the Department of Health Policy at Jefferson Medical College (Philadelphia, PA, USA), says that the effect of copayment (or ‘cost sharing’) on adherence is of great relevance to health economists, although the effect of copays varies with many factors, such as the socioeconomic status of the patient or population, the level of copay, age of the patient, and the type of disease.

With ‘benefit-based copay’, the benefit refers to clinical benefit, and the copay is limited to those with less serious illness. In other words, copays would be based on the actual clinical benefit a medication can give an individual, and the copays are scaled based on the importance and prevalence of the disease in a population. So, for a disease state such as asthma or heart disease – very common with serious clinical outcomes – the copay should be reduced or eliminated, to improve adherence and outcomes. As Dr. Nash states, “you have to understand the psychology of the copayment”. Importantly, copays would also vary within these long-term diseases based on the patient’s severity of the disease, and the benefit-based copay system would only be applied to drugs and diseases for which there is solid evidence that the benefit differs between patients with greater or lesser illness severity.

As health economists gain a greater understanding of the ‘psychology of copays’ and other determinants of adherence, HE research and public health policy initiatives will benefit as the research is applied to real-world scenarios.