Abstract
Background – Ghana ranks among the countries most affected by glaucoma in the world. Glaucoma is estimated to account for 20.6% of all cases of blindness in the country. In recent years, there has been a growing concern that anti-glaucoma medications listed on the National Health Insurance Scheme’s (NHIS) medicines list are not adequate to manage the disease. This has led to calls from different stakeholders for prostaglandin analogues, particularly latanoprost, to be added to the NHIS medicines list. However, the cost-effectiveness of this medication is yet to be established. Objective – To establish the cost-effectiveness of prostaglandin analogue as a first-line medication for treating primary open angle glaucoma (POAG) in Ghana. Method – A Markov Model was constructed to assess the life-time cost-effectiveness of treating a cohort of one thousand 55-year-old POAG patients with prostaglandin analogues compared to beta blockers. Effectiveness data was taken from literature. Cost data was obtained mainly from Ghana’s National Health Insurance Scheme (NHIS) medicines list for 2016 and the recently revised Ghana Diagnostic-related group (G-DRG) tariff lists. Costs of treatments not covered by the NHIS were estimated as the average of retail prices quoted by some leading pharmaceutical companies in Ghana. The effect of parameter uncertainty on cost-effectiveness was explored through one-way, two-way, and probabilistic sensitivity analyses. Results – Compared to beta blockers, prostaglandin analogues resulted in an incremental cost-effectiveness ratio (ICER) of USD 11,600; based on an estimated incremental gain of 105 quality-adjusted life years (QALYs), at an additional cost of USD 1,222,400. The probability that prostaglandin analogue is cost-effective compared to beta blockers at a willingness to pay threshold of USD 4,100 per QALY was 0.27. The ICER was not sensitive to the age of the cohort, the cost of prostaglandin analogues, or the probability of developing asthma. However, the ICER was sensitive to the age of the cohort and the cost of prostaglandin analogues when varied simultaneously. Conclusion – Given the existing evidence, prostaglandin analogue is not a cost-effective alternative to beta blockers as a first-line treatment for POAG in Ghana. The study, however, shows that further research to reduce decision uncertainty would be necessary if expected cost of research does not exceed USD 131 billion.