Understanding medication compliance and persistence from an economics perspective

Objectives: An increased understanding of the reasons for noncompliance and lack of persistence with prescribed medication is an important step to improve treatment effectiveness, and thus patient health. Explanations have been attempted from epidemiological, sociological and psychological perspectives. Economic models (utility maximization, time preferences, health capital, bilateral bargaining, stated preference, and prospect theory) may contribute to the understanding of medicines-taking behavior. Methods: Applying economic models to medication non-compliance. Traditional consumer choice models under a budget constraint apply to medication taking behavior in that increased prices causes decreased utilization. However, empirical evidence suggests that budget constraints are not the only factor affecting consumer choice around medicines. Examination of time preference models suggests that the intuitive association between time preference and medication compliance has not been investigated extensively, and has not been proven empirically. The health capital model has theoretical relevance, but has not been applied to compliance. Bilateral bargaining may present an alternative model to concordance of the patient-prescriber relationship, taking account of game-playing by either party. However, there is limited empirical evidence to test its usefulness. Stated preference methods have been applied most extensively to medicines use. Results: Evidence suggests that patients' preferences are consistently affected by side effects, and that preferences change over time, with age and experience. Prospect theory attempts to explain how new information changes risk perceptions and associated behavior but has not been applied empirically to medicines use. Conclusions: Economic models of behavior may contribute to the understanding of medicines use but more empirical work is needed to assess their applicability. Volume ** • Number * • 2008 V A L U E I N H E A L T H behaviour, reflected by the World Health Organization (WHO) definition for non-compliance as, “a multidimensional phenomenon determined by the interplay of five sets of factors: patientrelated, condition-related, therapy related, health system factors and social/ factors”(2). Explanations of patients' non-compliance with prescribed treatments have been attempted from many perspectives: epidemiological, sociological and psychological. More recently, economists have begun to work with psychologists to examine people's choice behavior in health-related decision-making more closely (12). These economic explanatory models may contribute to the understanding of medicine-taking behavior. In this paper we summarize existing knowledge around reasons for non-compliance. We then describe relevant economic models and present an argument for their use to further explain medication non-compliance. First we examine the more traditional economic theories: utility maximization (supply and demand), time preferences, and health capital. Next we explore extensions to these models including bilateral bargaining, stated preference, and prospect theory. In each section we provide a brief explanation of each model, relate the model to patient medication taking behavior and present an example. Existing knowledge around reasons for medication non-