Authors: Tina Felfeli, MD¹, Rafael N. Miranda, DDS², Clara C. Chan, MD, FRCSC³, David M. J. Naimark, MD, MSc, FRCPC⁴. ¹Department of Ophthalmology and Vision Sciences, University of Toronto, Ontario, Canada; Institute of Health Policy, Management and Evaluation, University of Toronto, Ontario, Canada, ²Toronto Health Economics and Technology Assessment (THETA) Collaborative, University Health Network, Ontario, Canada; Institute of Health Policy, Management and Evaluation, University of Toronto, Ontario, Canada, ³Department of Ophthalmology and Vision Sciences, University of Toronto, Ontario, Canada; Vision Science Research Program, Krembil Research Institute, Toronto Western Hospital, University Health Network, Ontario, Canada, ⁴Department of Nephrology, Sunnybrook Health Sciences Centre, Ontario, Canada; Institute of Health Policy, Management and Evaluation, University of Toronto, Ontario, Canada.

Author Disclosure Block: T. Felfeli, MD: None. R.N. Miranda, DDS: None. C.C. Chan, MD, FRCSC: None. D.M.J. Naimark, MD, MSc, FRCPC: None.

Title: Cost-Effectiveness of Preoperative Topical Antibiotic Prophylaxis for Endophthalmitis following Cataract Surgery

Abstract Body:

Purpose: To determine the cost-effectiveness of preoperative topical antibiotic prophylaxis for the prevention of endophthalmitis following cataract surgery.
Study Design: Decision-analytic microsimulation model for evaluation of cost-effectiveness.
Methods: Preoperative topical antibiotic prophylaxis costs and effects were projected over a life-time horizon in discrete time steps of one year for a simulated cohort of 100,000 adult patients (≥ 18 years old) requiring cataract surgery. We modelled a reduced risk of developing endophthalmitis amongst patients receiving prophylaxis relative to no-prophylaxis. The model estimated transition probabilities based on efficacy-adjusted visual acuity change in alive and death health states. Efficacy results were derived from pivotal population-based studies and Cochrane systematic reviews. Healthcare resource utilization and out of pocket expenses (2021 United States dollars [USD$]) and health utility values were obtained from the literature and discounted at 3% per year. Discounted, quality-adjusted life-years (QALYs), discounted lifetime costs, and the incremental cost-effectiveness ratio (ICER) of prophylaxis were estimated. We assumed a cost-effectiveness criterion of ≤ $50,000 per QALY gained. Deterministic sensitivity analyses were conducted to examine the impact of alternative model input values on the results.
Results: The mean incidence of endophthalmitis following cataract surgery for preoperative topical antibiotic prophylaxis versus no-prophylaxis was 0.035% (95% CI, 0-0.2%) and 0.043% (95% CI, 0-0.3%), respectively; a relative risk reduction of 18.6%. The mean life-time probability of a poor vision outcome for prophylaxis and no-prophylaxis was 4.478% and 4.479%, respectively. The mean life-time costs for cataract surgery with prophylaxis versus no-prophylaxis were $2,949 (95% CI, $2,653-$3,263) and $2,871 (95% CI, $2,589-$3,165), respectively; these amounts resulted in a mean life-time cost difference of $78 for prophylaxis. The QALYs associated with prophylaxis and no-prophylaxis were 17.32533 (95% CI, 12.95788-20.92013) and 17.32515 (95% CI, 12.95788-20.92013), respectively. The ICER was $441,225 per QALY gained for prophylaxis versus no-prophylaxis. Based on deterministic sensitivity analysis, the results were not sensitive to relative risk reduction of developing endophthalmitis with prophylaxis. Threshold analyses indicated that prophylaxis would be cost-effective if the incidence of endophthalmitis after cataract surgery was greater than 0.22% or if the price of the preoperative topical antibiotic prophylaxis was less than $10.
Conclusions: Assuming a cost-effectiveness criterion of $50,000 per QALY gained, general use of preoperative topical antibiotic prophylaxis is not cost-effective compared to no-prophylaxis for the prevention of endophthalmitis following cataract surgery. Preoperative topical antibiotic prophylaxis, however, would be cost-effective at a higher incidence of endophthalmitis and/or a substantially lower price for prophylaxis.