Lower drug prices and new payment policies in both the public and private sectors offer real opportunities to tackle the problem of poor medicines compliance, which currently costs the US as much as $290 billion a year, according to a new study.

Despite growing recognition of the problem, little progress has been made to improve medication adherence at a population level, say Aaron McKethan, Josh Benner and Alan Brookhart of medication adherence specialist firm RxAnte, reporting in the journal Health Affairs. 

However, "several new market and policy dynamics have the potential to substantially mitigate barriers to - and indeed trigger new investments in - improving medication adherence," they suggest.

One such change is the substantial and continuing decline in the cost of common chronic medications, largely because of the loss of patent protection. For US patients enrolled in Medicare's Part D programme, which provides them with prescription drug benefits, the average cost per day of treatment has declined from $1.50 per patient in 2006, when the programme was implemented, to $1.00 per patient in 2010 and is expected to reach $0.65 per patient by 2015.

"Lower effective drug prices for common chronic conditions have significantly improved the cost-effectiveness of several chronic therapies and have increased the likelihood that appropriate use of safe and effective medicines results in net cost savings from a payer and societal perspective," the authors write.

Another new development is that US health care payers in both the public and private sectors are now experimenting with new provider payment models which are designed to slow spending growth and achieve progressively better care quality. Such initiatives will emphasise the need to maximise the returns available from effective use of medicines, since they represent the most common medical intervention in health care, says the study.

Accountable care organisations (ACOs) are one such initiative. ACOs are formed by groups of doctors and other healthcare providers that have agreed to work together to coordinate care for Medicare enrolees. Under agreements which they enter into with the Centers for Medicare and Medicaid Services (CMS), ACOs take responsibility for the quality of care they provide for Medicare beneficiaries, in return for the opportunity to share in savings realised through such initiatives.

As of July 1, 154 ACOs across the US were participating in Medicare shared savings initiatives, covering more than 2.4 million Medicare enrollees, according to government figures.

"Newly-created ACOs will have new incentives to focus on improving medication adherence at a population level," write McKethan, Benner and Brookhart in Health Affairs, adding: "by our count, 20 of the 33 quality measures to which Medicare ACOs are accountable are related to the safe and effective use of medicines."

Given that they can share in the savings created by their efforts to slow healthcare spending, Medicare ACOs are likely to regard medication adherence as a priority, and they will be able to invest in improvements. This is because they will be accountable for slowing the growth of health care spending associated with Medicare Part A (hospital) and Part B (outpatient physician) services, but not Part D, they note.

"This means that ACOs can invest in steps to increase medication adherence, triggering increases in Part D spending for which they are not accountable, and benefit from resulting slower growth in utilisation rates for physicians and outpatient services in key patient subpopulations and in certain therapy areas," the authors note, adding: "this creates an important opportunity for ACOs to invest in increasing medication adherence and for CMS and researchers to investigate the policy incentives created by the current ACO regulations."