ABSTRACT
Clinical and health services researchers interested in studying nonadher-ence must be cognizant of costs for several reasons. First, on the patient level, adherence to prescribed regimens is a critical mediating variable when seeking to improve many patient outcomes. Thus, nonadherence to prescribed regimens reduces the efficacy of medical care and may limit patients from receiving the full benefit of their treatment. To the extent that patients pay for these treatments, their investment in health may be compromised. Second, beyond the effect on individual patients, nonadherence can be costly to health care providers, insurers, and society. For example, to the extent that following appropriate treatment regimens results in preventable emergency department visits and hospitalizations, nonadherence can result in substantial costs that might otherwise be averted. One dated study estimated that the cost of nonadherence in the United States, including hospital and nursing home admissions, lost productivity, premature deaths, and excessive treatments surpassed $100 billion per year (1). Another estimated that patient nonadherence accounted for between 2% and 6.5% of all hospital admissions (2). Finally, policymakers must also recognize the impact of costs on nonadherence. That is, patients who lack the resources to obtain prescribed treatments are at increased risk of nonad-herence. Unfortunately, those who lack these (often financial) resources (e.g., socioeconomically disadvantaged, older adults) are at greater risk of poor health outcomes and use of costly health care services.
