Observance: Définitions et méthodes de mesure: spécificités de l’observance des traitements topiques

Development and Validation of a Novel Questionnaire for Adherence with Topical Treatments in Psoriasis (QATOP)

BACKGROUND

Self-report measures are the most used methodologies for the evaluation of adherence to psoriasis topical treatment, although currently there is no standard questionnaire for this purpose.

OBJECTIVE

The present study aimed at developing a novel questionnaire (Questionnaire for Adherence to TOPical treatment [QATOP]) for the assessment of adherence to topical treatment in psoriasis.

METHODS

A questionnaire containing nine items organized into two parts (part 1: current patient treatment; part 2: adherence to treatment, amount used, and treatment-associated variables) was developed, supported by a systematic literature review, qualitative patient focus interviews, and expert-group input. Its content validity was determined by a pilot study of six patients. Adherence to topical treatment was then assessed in 35 patients with psoriasis, after 45 days of treatment, using the QATOP and a medication log. Associations between different items of the QATOP and the log were investigated.

RESULTS

Adherence results were 63.5 ± 29.2% for the log and 60.9 ± 24.4% for the QATOP, and were strongly correlated (R = 0.819, p < 0.001). Distinct posologic regimens were reported by patients, which, in some cases, were not the usual doses. Patients also reported using doses of medicine on each application that were markedly lower than required.

CONCLUSION

The QATOP is a valid and reliable self-report measure of adherence to topical treatment in patients with psoriasis. The use of this standard questionnaire could improve the methodological quality of adherence studies. Improvement of the clarity of posologic instructions is clearly urgently needed.

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.