The resolution of excess central retinal thickness in response to anti-VEGF therapy and the treatment burden were additionally similar between the 2 groups.
Although eyes with central retinal vein occlusion (CRVO) presented with worse visual acuity (VA) and more macular edema on average than eyes with hemiretinal vein occlusion (HRVO), the two groups were associated with a similar magnitude of visual acuity letter score (VALS) improvement.
Additionally, these new findings suggest the resolution of excess central retinal thickness in response to anti-VEGF therapy and the treatment burden were similar between the 2 groups.
“Thus, it appears that although anti-VEGF therapy is similarly effective in CRVO and HRVO with respect to the magnitude of VA improvement and resolving excess central retinal thickness, eyes with CRVO have an overall worse visual prognosis than do eyes with HRVO owing to factors other than macular edema already impairing vision at baseline,” wrote study author Paul C. VanVeldhuisen, PhD, The Emmes Company.
VanVeldhuisen and colleagues compared the baseline characteristics, treatment response, and treatment burden in participants with HRVO compared to CRVO in the SCORE2 trial.
Between September 2014 - November 2015, a total of 362 patients (305 patients with CRVO and 57 patients with HRVO) were randomly assigned to receive intravitreal injections of aflibercept, 2.0 mg or bevacizumab, 1.25 mg at randomization and every 4 weeks through month 5.
Primary outcomes were considered change from baseline in best-corrected electronic Early Treatment Diabetic Retinopathy Study (ETDRS) VALS at month 6. After assessment at month 6, those who met the protocol-defined criteria for a good response were randomized either to continuing treatment with their original study drug every 4 weeks or changing to a treat-and-extend regimen.
Then, after month 12, there was no protocol-defined treatment schedule and patients were treated by investigator discretion and observed through month 60.
From the total patient population (n = 362), 157 (43.4%) were female and the mean age was 68.9 years. A total of 21 of 57 patients with HRVO (36.8%) were Black, in comparison to 33 of 305 patients with CRVO (10.8%; P <.001).
Compared to eyes with CRVO, eyes with HRVO had a higher mean baseline VALS (54 versus 50; t test P = .04) and a lower mean baseline central subfield thickness (594 μm versus 678 μm; t test P = .01).
The treatment rates between months 12 - 23 were 0.36 (95% CI, 0.32 - 0.40) injections per month for patients with CRVO and 0.28 (95% CI, 0.19 - 0.36) for patients with HRVO (P = .11).
Data show the mean VALS from months 1 to 24 of an HRVO study eye exceeded that of a CRVO study eye by 5.5 (95% CI, 1.5 - 9.5; P = .01). This was found to be consistent with the magnitude of the VALS difference between eyes with CRVO and HRVO at baseline.
Additionally, eyes with CRVO presented at baseline with more macular edema than eyes with HRVO (difference in CST, 86 μm; 95% CI, 48 - 124; P <.001), with no difference in CST between groups at months 1 - 24.
Investigators noted that patients in both groups required 3 - 4 anti-VEGF injections in the second year of follow-up and by the end of year 2, only 22% to 25% of eyes in each group had achieved complete resolution of macular edema.
“This suggests that close monitoring and continued treatment as indicated are needed to optimize the long-term visual and anatomic outcomes of patients treated initially with anti-VEGF therapy for CRVO-associated or HRVO-associated macular edema,” VanVeldhuisen concluded.
The study, “Baseline Characteristics and Outcomes After Anti–Vascular Endothelial Growth Factor Therapy for Macular Edema in Participants With Hemiretinal Vein Occlusion Compared With Participants With Central Retinal Vein Occlusion,” was published in JAMA Ophthalmology.