A comparison of measures used to describe adherence to glaucoma medication in a randomised controlled trial

Background:Understanding the magnitude of non-adherence in pre-marketing clinical trials and clinical practice is essential. However, accurately measuring non-adherence to medication is problematic, and the variety of adherence measures and/or calculation methods has led to highly variable results.Purpose:To compare commonly used methods for measuring adherence to eye drop therapy in order to assess which methods achieve the most complete datasets over an 8-month monitoring period, to quantify the magnitude of variance in adherence estimations and to review the different methods used to calculate or interpret adherence data.Methods:Adherence was measured electronically for 8 months by participants administering eye drops using a Travalert® dosing aid. The mean number of Travalert dosing aid recorded doses administered over the monitoring period was used to calculate a percentage adherence score. In addition, the value of graphically presenting Travalert dosing aid data to classify patterns of adherence be...