Adherence to topical therapy decreases during the course of an 8-week psoriasis clinical trial: commonly used methods of measuring adherence to topical therapy overestimate actual use.

INTRODUCTION: Medication nonadherence is common throughout medicine, and research into this area is increasing; however, knowledge about topical medication adherence is limited.
METHODS: A total of 30 patients were enrolled in a clinical trial for psoriasis and followed up for 8 weeks using 3 methods of adherence monitoring: electronic monitoring caps; medication logs; and medication usage by weight.
RESULTS: Adherence rates calculated from the medication logs and medication weights were consistently higher than those of the electronic monitors (P <.05). Electronically measured adherence rates declined from 84.6% to 51% during the 8-week study (P <.0001). Female sex and increasing age by 1 year predicted improved adherence of 5% and 0.8%, respectively (P <.0001). The number of treatment gaps increased from the first half to the last half of the study, and weekend days were overrepresented in treatment gaps.
CONCLUSION: Medication logs and weights do not ensure medication adherence to topical therapy. Electronic monitoring allows a more precise method of adherence measurement.