Candidate for the Lee B. Lusted Student Prize Competition
Purpose: To determine the most cost-effective treatment option for patients with newly-diagnosed clinically significant diabetic macular edema (CSDME): focal laser photocoagulation (L), focal laser plus intravitreal triamcinolone (L+T) injections, and intravitreal ranibizumab injections with the focal laser (L+R) or delayed laser with ranibizumab injections (DL+R).
Methods:
We developed a Markov decision analysis model to compare the incremental cost effectiveness ratio (ICER) of treating newly-diagnosed CSDME with L, L+R, DL+R or L+T. The model followed a hypothetical cohort of patients, 57 years of age with CSDME over a 25 year time horizon. Different levels of best corrected visual acuity (BCVA) were used as health states. The distribution of BCVA at the baseline, year 1 and year 2 or later were obtained from a recent DRCRnet randomized controlled trial. We used a societal perspective, measuring direct medical costs of treatment and long-term care of CSDME as well as quality-adjusted life years (QALYs) gained with 3% annual discount rates. Sensitivity analysis was conducted to test uncertainty in the model assumptions.
Results:
Under the base model with the use of ranibizumab, over 25 years the expected cost for a single patient with newly-diagnosed CSDME receiving L, L+R, DL+R, and L+T were $15505, $53750, $56917, and $19369, while the effectiveness were 10.43, 10.83, 10.99, and 9.57 QALYs, respectively. The ICER of DL+R over L was $71271/QALY, L+R over L was $89903/QALY and L dominated L+T. With the use of bevicizumab instead of ranibizumab, The ICER of DL+B over L was $11138/QALY and L continued to dominate L+T. L+B provided fewer QALYs at a higher cost per QALY than DL+B.
Conclusion: An interesting finding from our analysis is the impact of using bevicizumab instead of ranibizumab in the model. Although not approved by the FDA, many providers will treat CSDME using bevicizumab since it is considerably cheaper than ranibizumab ($348 vs. $2337 per injection) and is assumed to have similar efficacy. Given similar effectiveness, the price differential between these two anti-VEGF agents can have a dramatic impact on the incremental cost effectiveness as observed in our analysis. The risk of cerebrovascular accident would need to be at least 1.5% greater among patients receiving bevicizumab relative to ranibizumab for ranibizumab to become the more cost-effective treatment alternative.