Atrial fibrillation and the 'other drug problem': reducing non-adherence with technology.

The terms compliance, adherence, concordance, and persistence are used to characterize important aspects of medication-taking behaviour. According to the International Society for Pharmacoeconomics and Outcomes Research Medication Compliance and Persistence Work Group, medication compliance (or adherence) is defined as ‘the extent to which a patient acts in accordance with the prescribed interval and dose of a dosing regimen’; while medication persistence is ‘the duration of time from initiation to discontinuation of therapy’. The medical profession is well aware that non-adherence to recommended medications represents a worldwide problem, encompassing a large variety of illnesses, treatments, and age groups. Non-adherence leads to worrying consequences, for patients, health professionals, and healthcare systems. According to the World Health Organization (WHO), almost 50% of patients do not take medications as prescribed, and evidence shows that noncompliance with medications leads to an inadequate control of the illness, placing patients at a higher risk for complications and adverse outcomes. 5 Expenditure on direct and indirect consequences of non-adherence to treatment (e.g. hospital admissions, underutilized drugs, and disease progression) represents a substantial burden for healthcare systems. Indeed, in 2003 the WHO called for initiatives to improve adherence in chronic conditions, claiming that ‘increasing the effectiveness of adherence interventions may have a far greater impact on the health of the population than any improvement in specific medical treatment’. Non-adherence is a frequent phenomenon: approximately only one-third of patients fully comply with prescribed treatment. For long-term therapies, adherence begins to decline within the first 10 days. Clinical and economic consequences are huge: in the USA 43% of the general population, 55% of the elderly, and 54% of teenagers are not compliant with their treatment causing 10–25% of hospital and nursing home admissions as well as 125 000 deaths annually. The costs for the healthcare system are as high as $100 billion annually, with almost half of them due to drug-related hospitalization. Since healthcare costs represent an ever-increasing proportion of the national budget, it remains a toptiered issue in politics. With a non-adherence rate of 50%, the UK has £4 billion of medicines not used correctly; as a consequence, non-adherence is responsible for 11–30% of UK hospital admissions. Across Europe, the lack of compliance with prescriptions causes E1.25 billion of healthcare expenditure, as well as nearly 200 000 deaths annually. Conscious of the growing value that adherence has in current patient care, we wish to focus on this important topic, paying particular attention to the situation in the field of cardiology and exploring the characteristics of an ideal adherence monitoring programme based on technology.