Why individual-level interventions are not enough: Systems-level determinants of oral anticancer medication adherence

Nonadherence to oral anticancer medications (OAMs) in the United States is as low as 33% for some cancers. The reasons for nonadherence to these lifesaving medications are multifactorial, yet the majority of studies focus on patient-level factors influencing uptake and adherence. Individually based interventions to increase patient adherence have not been effective, and this warrants attention to factors at the payor, pharmaceutical, and clinical systems levels. Based on the authors' research and clinical experiences, this commentary brings fresh attention to the long-standing issue of OAM nonadherence, a growing quality-of-care issue, from a systems perspective. In this commentary, the key driving factors in pharmaceutical and payor systems (state and federal laws, payor/insurance companies, and pharmaceutical companies), clinical systems (hospitals and providers), and patient contexts that have trickle-down effects on patient adherence to OAMs are outlined. In the end, the authors' recommendations include examining the influence of laws governing OAM drug pricing, OAM supply, and provider reimbursement; reducing the need for prior authorization of long-approved OAMs; identifying cost-effective ways for providers to monitor nonadherence; examining issues of provider bias in OAM prescriptions; and further elucidating in which contexts patients are likely to be able to adhere. These recommendations offer a starting point for an examination of the chain of systems influencing patient adherence and may help to finally resolve persistently high levels of OAM nonadherence.