Persistency rates for prostaglandin and other hypotensive eyedrops: population-based study using pharmacy claims data

BACKGROUND: Effective management of ocular hypertension requires patients to be persistent with their treatment regimen. We evaluated patients' persistency with hypotensive eyedrops commonly used to treat glaucoma and ocular hypertension. METHODS: This large, population-based, retrospective, cohort study used pharmacy claims data for concessional patients from the Australian Pharmaceutical Benefits Scheme (July 1999-June 2005). Resupply rates for prostaglandins, beta-blockers, alpha-agonists and carbonic anhydrase inhibitors were analysed using life tables and Cox regression. Two populations, based on patients' supply histories, were examined: (i) 'new to this eyedrop'- patients who had used other hypotensive eyedrops before (presumably, previously diagnosed with glaucoma or ocular hypertension); and (ii) 'new to any eyedrop'- patients who were using their first hypotensive eyedrop (presumably, newly diagnosed with glaucoma or ocular hypertension). RESULTS: Data were obtained for 14,359,618 supplies of commonly used hypotensive eyedrops to 357,099 concessional patients. For both populations, resupply rates were highest for prostaglandins or the dorzolamide-timolol combination eyedrops, compared with beta-blockers, alpha-agonists or carbonic anhydrase inhibitors. Among the prostaglandins, there was no significant difference in the risk of ceasing supply between latanoprost and bimatoprost, but the risk was significantly higher for travoprost. CONCLUSIONS: Based on resupply rates from a national pharmacy claims database, patients supplied with ocular hypotensive eyedrops were most persistent with prostaglandin (bimatoprost, latanoprost and travoprost) and dorzolamide-timolol combination eyedrops. Among the prostaglandins, persistency was highest with, and similar between, bimatoprost and latanoprost. Persistency should be taken into account when selecting the most appropriate eyedrop to treat glaucoma and ocular hypertension.