Objective: To determine the persistence rates of patients who started taking topical intraocular pressure (IOP)-lowering monotherapy in a Singapore eye hospital.
Methods: This was a retrospective review of patients who started taking a single IOP-lowering medication between October 1, 2005, and September 30, 2006. Pharmacy dispensing records were traced for 3 years from the date of first prescription. A patient was defined as persistent if he or she was prescribed the same medication before or within 90 days after the previous prescription had lapsed during this period. Persistence was assessed after 1 and 3 years.
Results: A total of 2781 patients started taking topical IOP-lowering monotherapy during the 1-year study period. The mean (SD) age was 61.1 (15.7) years; 50.2% were male, and most were Chinese (81.1%) or Singaporean residents (85.4%). After 1 year, only 22.5% of patients (626 of 2781) persistently received the same therapy, which decreased to 11.5% (320 of 2781) after 3 years. Prostaglandin analogues had better persistence rates at 1 year compared with timolol maleate (29.6% vs 23.7%; P = .004) and all other medications combined (29.6% vs 20.6%; P < .001). Those who were not persistent at year 1 were younger (P < .001) and more likely to not be Singaporean (P = .008), not receiving government subsidies (P < .001), and receiving unilateral therapy (P < .001).
Conclusions: In this hospital-based study, the persistence rate of patients who started taking topical IOP-lowering monotherapy was low after 1 (22.5%) and 3 years (11.5%). These rates are lower than in previous studies in Western countries and may have implications for glaucoma care in Singapore and other parts of Asia.