Methodologies for medication adherence evaluation: Focus on psoriasis topical treatment.

Adherence to topical treatment has been less studied in comparison with systemic therapeutic regimens and is poorly understood. High-quality research on this area is essential to outline a strategy to increase medication adherence and clinical outcomes. For a more comprehensive understanding of this issue, a systematic review of the methodologies for topical treatment adherence evaluation in psoriasis was undertaken. Twenty one studies were selected from the literature which used six different adherence methodologies. Merely three studies used multiple adherence measurement methods. The most used method was questionnaire (44%) which was also associated with higher variability of the adherence results. One possible explanation is the lack of a validated questionnaire designed specifically for the evaluation of adherence to topical treatment. Only one method (medication weight) takes into consideration the applied dose. However, the estimation of the expected weight is complex, which renders this method, as used presently, less effective. The use of a dosing device could improve its accuracy and be helpful to clearly instruct the patients about the correct dose. As there is no single method that allows an accurate and complete assessment of adherence it is recommended to use a combination of methods, including self-report and medicines' weight measurements.