Cost-effectiveness analysis of iStent trabecular microbypass stent for patients with open-angle glaucoma in Colombia
Objective: To estimate cost-effectiveness of trabecular micro bypass stent versus laser trabeculoplasty or medications only, for patients with open-angle glaucoma in setting of Colombian System Health. Methods: This is a cost-effectiveness analysis that based its assumptions in external data sources, used to extrapolate the quality of life related to health, survival and costs. A Markov model, with stages from 0 (ocular hypertension without glaucoma) to 5 and bilateral blindness, was developed inclusive of Colombian older than 40 years in 2018, from a societal perspective, comparing trabecular micro-bypass stents versus, laser trabeculoplasty, timolol+dorzolamide+brimonidine, timolol+dorzolamide+latanoprost, or timolol+dorzolamide+brimatoprost, in terms of clinical and economic outcomes over a lifetime horizon. Both costs and health outcomes had an annual rate discount of 5%. Health outcomes were evaluated in terms of QALYs related with loss of visual acuity. Trabecular micro-bypass costs include the joint use of timolol, the costs of laser trabeculoplasty include the combined use of timolol+dorzolamide. Results: Trabecular micro-bypass stents were estimated to have 127,971 more discounted QALYs, versus laser trabeculoplasty; 405,982, versus timolol+dorzolamide+brimonidine; and 378,287, versus timolol+dorzolamide+latanoprost or timolol+dorzolamide+brimatoprost. Cumulative costs with trabecular micro-bypass stents at 40 years was $13,252,318 lower than laser trabeculoplasty; $6,403,534, lower than timolol+dorzolamide+brimonidine; $22,311,064, lower than timolol+dorzolamide+latanoprost; and $29,156,113 lower than timolol+dorzolamide+brimatoprost. Conclusions: Trabecular micro-bypass stent is a highly cost-saving strategy due to more QALYs related to a lower rate of the population with loss of visual acuity in the long term, and because the costs associated with additional medications and complications are lower with trabecular micro-bypass stents.