[Early adherence to anti-glaucoma therapy: An observational study]

Objectives: Glaucoma is a major cause of blindness, preventable by a regular therapy. Thus, a good knowledge of patients' adherence to preventive therapy is critical to improve disease management. Early persistence to first-line glaucoma therapy is poorly documented in France. We verified to what extent first-line glaucoma therapy was interrupted within the 12 months following initiation and how this interruption varied with patients' characteristics and drug classes.

Methods: Patients newly-treated with chronic glaucoma therapy (prostaglandins, beta-blockers alone or combined with another therapy, and topical carbonic anhydrase inhibitors) between 2005 and 2008 were identified in the French National Claims data (1/97th random sample). Twelve-month persistence was defined by the presence of the first-line drug class (≥1dispensation) between the 12th and 24th months following initiation. Twelve-month persistence was compared between patients according to the first-line drug classes and baseline characteristics. Proportion of days covered (12 months) and number of quarters with initiated drug class (24 months) were also studied.

Results: Among 5331 patients initiated with chronic glaucoma therapy in monotherapy (63% aged ≥60 years old, 57% females), initiated therapy mainly consisted of prostaglandins (43%) and beta-blockers alone (32%). Only 45% of the patients were persistent to first-line therapy 12 months after initiation. Salient differences in persistence rates appeared between drug classes (P<0.0001): from 59% with prostaglandins to 26% for topical carbonic anhydrase inhibitors. Better results also appeared for prostaglandins with other dimensions of adherence. Non-persistent patients were more likely younger than 40, or conversely aged≥80 (P<0.0001). They were also more likely to necessitate social assistance for therapy (P=0.0007). No salient difference appeared as to gender.

Conclusions: Our findings confirm the low early persistence of first-line therapy, despite better results for prostaglandins. Education of patients and identification of barriers to adherence could contribute to improve quality of care.