Cost-effectiveness of treatment of diabetic macular edema

Abstract

Background: Macular edema is the most common cause of vision loss among patients with diabetes.

Objective: To determine the cost-effectiveness of different treatments of diabetic macular edema (DME).

Design: Markov model.

Data sources: Published literature and expert opinion.

Target population: Patients with clinically significant DME.

Time horizon: Lifetime.

Perspective: Societal.

Intervention: Laser treatment, intraocular injections of triamcinolone or a vascular endothelial growth factor (VEGF) inhibitor, or a combination of both.

Outcome measures: Discounted costs, gains in quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs).

Results of base-case analysis: All treatments except laser monotherapy substantially reduced costs, and all treatments except triamcinolone monotherapy increased QALYs. Laser treatment plus a VEGF inhibitor achieved the greatest benefit, gaining 0.56 QALYs at a cost of $6975 for an ICER of $12 410 per QALY compared with laser treatment plus triamcinolone. Monotherapy with a VEGF inhibitor achieved similar outcomes to combination therapy with laser treatment plus a VEGF inhibitor. Laser monotherapy and triamcinolone monotherapy were less effective and more costly than combination therapy.

Results of sensitivity analysis: VEGF inhibitor monotherapy was sometimes preferred over laser treatment plus a VEGF inhibitor, depending on the reduction in quality of life with loss of visual acuity. When the VEGF inhibitor bevacizumab was as effective as ranibizumab, it was preferable because of its lower cost.

Limitation: Long-term outcome data for treated and untreated diseases are limited.

Conclusion: The most effective treatment of DME is VEGF inhibitor injections with or without laser treatment. This therapy compares favorably with cost-effective interventions for other conditions.

Primary funding source: Agency for Healthcare Research and Quality.

Figure 1

Markov Model Schematic VEGF=Vascular Endothelial Growth Factor The six strategy alternatives to the right of the decision node (square box) represent the six strategies for comparison, each progressing within the Markov model. The gray box represents the Markov model transitions for diabetic macular edema progression. Visual Acuity categories 1-6 represent visual acuity states (Table 1). Solid arrows represent possible worsening (Progression) within a given month, and dashed arrows represent the potential for improvement or progression within a given month while on treatment. On-treatment states are subject to risk of complications (arterial thromboembolic events, glaucoma, cataract, and other major or minor complications). In the base case, treatment was stopped after one year for all strategies, sooner if an arterial thromboembolic event or severe glaucoma.

Figure 2

One-Year Treatment and Lifetime Treatment Cost-Effectiveness Frontiers Representing the discounted lifetime costs and QALYs associated with the six strategies. (A) represents the main analysis, one year of treatment with lifetime followup (B) represents lifetime treatment with 3 VEGF-inhibit or injections per year (monotherapy or combination therapy), 1 triamcinolone injection per year (monotherapy or combination therapy), 1 laset treatment every other year in laser montherapy, and no additional laser treatments in combination therapy strategies. The solid black line indicates the cost-effectiveness fronties, which represents the most cost-effective series of strategies (achieving the greatest relative benefit for the lowest cost). Incremental cost-effectiveness ratios (ICERs) are indicated in $/QALY, representing the cost of additional effectiveness relative to the next best strategy (here, the preferred strategy of laser + VEGF-inhibitors is compared to laser + triamcinolone, with an ICER of $12,410/QALY with on year of treatment, and an ICER of $26,477 with treatment over a lifetime). The strategies that form the cost-effectiveness frontier (laser + triamcinolone and laser + VEGF-inhibitors, each depicted with a black dot) dominate those to the right of the frontier (gray dots) because they are either more effective and costless (strong dominance), or have better cost-effectiveness ratio (weak dominace). VEGF=Vascular Endothelial Growth Factor QALY=Quality-Adjusted Life Year