Cost-effectiveness analysis of early versus late switching in treatment-naïve patients with refractory diabetic macular oedema in the Turkish population: real-world data from the Bosphorus DME study group, report number 5

Clinical relevance Diabetic macular oedema (DME) is a leading cause of visual impairment worldwide. Real-world evidence is essential for understanding treatment effectiveness and guiding practical decision-making in routine clinical care.Background The aim of this work is to evaluate the cost-effectiveness of early versus late switching to intravitreal aflibercept or ranibizumab in eyes with DME refractory to intravitreal bevacizumab loading treatment.Methods This multicentre retrospective study included treatment-naïve refractory DME eyes that initiated bevacizumab between 2021 and 2023. Eyes were divided into three groups: no switch, early switch (3–6 months), and late switch (after 6 months). Public healthcare costs from 2021–2023 were used to calculate the cost per 0.1 improvement in best-corrected visual acuity (BCVA) and per 100 μm reduction in central macular thickness. Cost-effectiveness ratio and incremental cost-effectiveness ratio analyses were performed.Results A total of 229 eyes in the no-switch group, 328 eyes in the early-switch group, and 63 eyes in the late-switch group were analysed. At month 12, the greatest BCVA gain was observed in the early-switch group (p = 0.02). Mean injection numbers were 5.7 ± 1.4 (no-switch), 7.2 ± 1.5 (early-switch), and 6.6 ± 1.4 (late-switch) (p < 0.001). Cost-effectiveness ratio for visual acuity improvement was €4,838, €10,395, and €10,848 for the no-switch, early-switch, and late-switch groups, respectively. Incremental cost-effectiveness ratio analysis showed additional costs of €15,654 for early switching and €54,856 for late switching compared with no switching. Central macular thickness reduction was greatest in the no-switch group and lowest in the late-switch group (p = 0.05).Conclusion Although early switching yields the greatest visual improvement and faster rehabilitation, it incurs higher costs. The no-switch strategy provided modest visual improvement at the lowest cost, resulting in the most favourable cost-effectiveness ratio. Late switching produced limited benefit at high cost, rendering it an unfavourable option. Treatment decisions should balance clinical efficacy and cost-effectiveness on an individual basis.