The use of medication adherence guidelines in medication taking behaviour research.

Medication nonadherence continues to be a serious issue in a range of long-term medical conditions and has been studied extensively over the past few decades. However, despite the plethora of research studies on medication adherence, poor methodological rigour in many studies has contributed to limited generalisability of the positive findings, limited impact on patients' medication adherence, and inability to compare between studies. This paper focuses on current guidelines designed specifically for research on medication adherence. It discusses key elements to consider during study design, selection of adherence measurements, and reporting on medication adherence research, to ensure a higher quality of research in medication adherence. Overall, there appears to be variations in adherence terminology reported in the literature despite improvements in defining medication taking behaviour and the availability of taxonomies. In addition, limited guidance exists on how best to measure adherence. Recommendations are provided on appropriate adherence measures for the adherence behaviour being investigated, including careful consideration of adherence concepts, validity of adherence instruments, appropriate instrument selection, definition of nonadherence threshold, and how to report medication adherence. Improving adherence research requires greater clarity and standardisation of descriptions of nonadherence behaviour, increased methodological rigour in study designs, better selection of adherence measurements, and comprehensive reporting.