Abstract
Purpose:
The Tube versus Trabeculectomy Trial showed that the increasingly popular tube-shunt procedures may be similarly effective in lowering IOP with lower rates of failure and reoperation when compared to trabeculectomy1. While the TVT study demonstrated clinical effectiveness of both procedures, evidence on cost-effectiveness is limited. This study sought to compare the cost-effectiveness of trabeculectomy with mitomycin C to Baerveldt 350-mm2 implant.
Methods:
Using Markov modeling, the cost effectiveness of the procedures was evaluated from a societal perspective. A comprehensive literature review was conducted to identify clinically relevant probabilities of health states for each procedure including rates of success, number of supplemental medications, rates of severe complications and associated visual outcomes. Costs were identified from Medicare CPT/APC reimbursement codes and Red Book medication costs. Patient derived utilities were based on both visual field and visual acuity outcomes and represented by Quality Adjusted Life Years (QALYs). The hypothetical societal limit to resources was included using the willingness to pay threshold per QALY gained (WTP). Costs and utilities were discounted at 3% per year. Uncertainty was assessed using deterministic sensitivity analyses.
Results:
Using a five years time horizon, trabeculectomy was less costly ($8881 versus $11811) than tube insertion. Patient related utility was slightly more favorable in the tube group than trabeculectomy group (3.49 QALYs versus 3.43 QALYs). This resulted in a cost effectiveness ratio of $2592/QALY for trabeculectomy and $3384/QALY for tube insertion. Assuming a WTP of $50,000, trabeculectomy is the preferred option. However, if WTP is $100,000, the tube shunt is preferred. The model was sensitive to rates of failure for each procedure but was robust relative to incidence of complications and generic versus branded medications.
Conclusions:
Trabeculectomy provides a more cost effective option than Baerveldt tube shunt for the management of glaucoma. However, Baerveldt does provide slightly higher patient utility at five years and is the preferred option if the willingness to pay threshold is $100,000 per QALY gained. Future head to head clinical trials should consider costs and visual field outcomes in addition to more traditional glaucoma measures.
Keywords: 460 clinical (human) or epidemiologic studies: health care delivery/economics/manpower •
462 clinical (human) or epidemiologic studies: outcomes/complications •
466 clinical (human) or epidemiologic studies: treatment/prevention assessment/controlled clinical trials