Aims and purpose: Adherence to long-term treatment regimens for primary open-angle glaucoma holds a challenge for both clinicians and patients. The study aims were to (i) establish the magnitude of travoprost non-adherence using an Electronic Adherence Monitor (EAM), (ii) compare electronic with patient self-reported adherence, and (iii) explore the application of a previously reported method of graphically presenting adherence data to a larger cohort over a longer monitoring period.
Methods: A cohort study of patients using travoprost for glaucoma or ocular hypertension was conducted. All participants used an EAM and adherence data were collected prospectively for 2 months. Self-reported adherence was obtained using the Morisky Medication Adherence Scale (MMAS); patients also reported frequency of missed doses. Potential predictors of adherence were collected via a structured interview. EAM-recorded interdose intervals were plotted graphically.
Results: Of 100 patients invited to participate, 98 consented and EAM data were collected successfully from 88 participants. The median EAM adherence score for the cohort was 88.9% (interquartile range: 71.2, 92.2). When dichotomised (≥80%: adherent; <80%: non-adherent), EAM identified 36.7% as non-adherent and MMAS 12.2%. EAM data were used to classify five types of adherence behaviour including a category representing levels of ≥97% maintained by 21% of participants.
Conclusion: EAM revealed good adherence to glaucoma monotherapy but poor agreement with patient self-reported adherence. An adherence category of persistent and exceptionally high adherence to travoprost over a 2-month period was identified.