Relationship between electronically measured medication adherence and vision-related quality of life in a cohort of...

To investigate whether electronically measured medication adherence is associated with vision-related quality of life (VRQoL) in patients with open-angle glaucoma.

This is a 3-year prospective cohort study of 79 subjects with open-angle glaucoma at a Veterans Affairs medical centre. Participants returned a medication event monitoring system (MEMS) for their glaucoma eye-drops and had at least two visits with glaucoma during the study period. Those taking less than 80% of prescribed glaucoma medication doses were considered to be non-adherent. Subjects were interviewed using the National Eye Institute's Visual Function Questionnaire-25 (VFQ-25) at baseline and after 3 years.

Thirty per cent (n=24/79) of participants took less than 80% of prescribed doses of their glaucoma medications at baseline. Patients who did not adhere to their medications at baseline had lower mean composite VFQ-25 scores at baseline (70.66±20.50 vs 75.91±19.12, standardised mean difference=0.27) and after 3 years (71.68±21.93 vs 76.25±21.67, standardised mean difference=0.21). Visual acuity (P=0.03), but not visual field severity (P=0.13) or medication adherence (P=0.30), was significantly associated with composite VFQ-25 score in an adjusted model.

Subjects who were non-adherent to their glaucoma medications at baseline as assessed by a MEMS device reported lower VRQoL than adherent subjects at baseline and after 3 years. However, visual acuity was significantly associated with VRQoL. Future studies should assess whether improved adherence to eye-drops impacts VRQoL in patients with glaucoma.