Changes in adherence and associated factors among patients on newly introduced prostaglandin analog and timolol fixed-combination therapy

PURPOSE: We investigated patient adherence and factors related to a newly introduced prostaglandin analog and timolol fixed-combination eye drops (PGTFC). PATIENTS AND METHODS: The Glaucoma Research on Adherence to fixed-Combination Eye drops in Japan (GRACE) study group performed a nationwide prospective questionnaire survey. Participants in this study were patients with glaucoma who were scheduled to receive any type of PGTFC for the first time. The participants answered a questionnaire on the day of PGTFC introduction and again at a return visit 4–6 weeks after PGTFC introduction. The physicians in charge were asked to complete a separate questionnaire on the day of PGTFC introduction. One of two leaflets was randomly delivered to each participant before the description of the PGTFC. One leaflet explained how to correctly instill the eye drops, and the other explained the clinical meaning of intraocular pressure reduction in addition to explaining how to correctly instill the eye drops. Nonadherence was defined as forgetting to instill the eye drops one or more times during the week before the return visit. RESULTS: In total, 3,597 patients (age, 68.4±12.2 years) met the study protocol requirements. PGTFC introduction significantly reduced the number of antiglaucoma eye drops from 1.93±0.78 to 1.34±0.54 (P<0.0001) and significantly improved adherence (P<0.00001). Factors significantly associated with nonadherence at the return visit included a history of nonadherence as reported by either the patient or their physician before introduction, acceptable instillation times as reported by the patient, and burdensome eye drop instillation as reported by the patient. No significant difference was observed between the two leaflets in terms of their effects on adherence. CONCLUSION: PGTFC significantly improved adherence and some of the factors that were significantly associated with adherence. REGISTRATION NUMBER: UMIN000013696