Using the Medication Adherence Reasons Scale (MAR-Scale) to identify the reasons for non-adherence across multiple disease conditions.

Purpose: With more than 50% of the individuals on chronic conditions not taking medicines as prescribed, it is essential for health care providers to understand the reasons, so that adherence-related conversations can be initiated and focused appropriately. Measuring medication non-adherence is complex, because patients are often on multiple medications and take them via various modes of administration such as orally, by injection, or topically, and at various frequencies such as daily or weekly. The Medication Adherence Reasons Scale (MAR-Scale) is a twenty-item, self-reported, comprehensive scale developed to measure two aspects of medication non-adherence: the extent or frequency of non-adherence and reasons for non-adherence. The objective of this study was to identify the top reasons, in 17 distinct chronic disease conditions, reported by patients for being non-adherent across various modes and frequencies of the corresponding medications. Internal reliability of the MAR-Scale was also assessed in each condition. Patients and methods: Results were derived from Kantar Health's US 2017 National Health and Wellness Survey (NHWS), a self-administered, annual, Internet-based cross-sectional survey of 75,000 adults (≥18 years). The survey sample was drawn from an Internet panel and was stratified according to age, gender, and ethnicity in order to represent the US adult population based on the US Census Bureau. Respondents to the 2017 NHWS who self-reported taking prescription medication(s) to treat one of the 17 conditions were invited to complete the MAR-Scale in a follow-up online survey, reporting on reasons for non-adherence in the past 7 days (daily medications) or four weeks (weekly), with non-adherence defined as any reported non-adherence in the corresponding timeframe for medicines taken orally, by injection, and topically. Results: MAR-Scale data were obtained from 15,672 respondents in one or more conditions, modes, and frequencies. MAR-Scale reliability ranged from Cronbach's alpha of 0.861 in multiple sclerosis to 0.973 in psoriasis. For daily orals, non-adherence ranged from 25.2% in diabetes to 63.7% in eczema. The most common reasons across conditions were "simply missed it," "side effects," and "concern about long-term effects." Conclusion: The MAR-Scale demonstrates acceptable reliability in multiple chronic disease conditions and across modes and frequencies of administration.