A pharmacoeconomic analysis to determine the relative cost-effectiveness of bimatoprost 0.03% eye drops and brimonidine 0.2% eye drops in patients of primary open-angle glaucoma/ocular hypertension

Abstract

Aims: The aim was to compare efficacy and cost-effectiveness of bimatoprost 0.03% and brimonidine 0.2% in primary open-angle glaucoma (POAG)/ocular hypertension (OHT). Settings and Design: Open, randomized, cross-over, comparative study. Materials and Methods: Forty patients of POAG or OHT with intraocular pressure (IOP) <30 mm Hg were included in the study after a written informed consent. The patients were divided randomly into two groups of 20 patients each. Patients of group A were administered bimatoprost 0.03% eye drops once daily, and those of group B brimonidine 0.2% eye drops twice daily for a period of 4 weeks. After a washout period of 4 weeks, the patients were crossed over that is, group A was administered brimonidine 0.2% and group B bimatoprost 0.03%. Fall in IOP at 4 weeks was recorded. The daily cost of each drug was calculated by maximum retail price and the average number of drops per bottle. The cost-effectiveness was then calculated as the cost of drug/mm Hg fall in IOP. Statistics: Independent samples t-test was used to compare the efficacy of both drugs. Results: IOP lowering with bimatoprost (8.9 ± 1.598 mm Hg) was significantly (P < 0.0001) higher than brimonidine (6.55 ± 1.26 mm Hg). The number of drops/ml were 33.43 ± 0.52 and 25.49 ± 0.26, respectively, for bimatoprost and brimonidine. Treatment with bimatoprost was costlier than brimonidine with daily costs/eye Rs. 4.02 ± 0.06 and 3.14 ± 0.03, yearly costs/eye Rs. 1467.46 ± 20.74 and 1147.75 ± 11.15, respectively. Bimatoprost was more cost-effective than brimonidine with the cost-effectiveness ratio (CER) respectively Rs. 13.10 ± 2.61/mm Hg and Rs. 13.96 ± 2.86/mm Hg. Incremental CER Rs. 10.43/mm Hg implies lower costs/mm Hg extra IOP lowering by bimatoprost than Rs. 13.96 for brimonidine. Conclusion: In spite of being costlier, bimatoprost is more efficacious and cost-effective than brimonidine