Ophthalmology, January 2017
Grunwald et al. estimated the incidence, size, and growth rate of geographic atrophy (GA) during 5 years of follow-up among participants receiving anti-VEGF therapy in the Comparison of Age-Related Macular Degeneration Treatments Trials (CATT). The authors found that development of GA was common at 5 years, and they identified several associated risk factors.
This was a cohort study within CATT. A total of 1,185 CATT participants were randomly assigned to ranibizumab or bevacizumab regimens. They were released from protocol treatment at 2 years and were examined at approximately 5 years (n = 647). Two masked graders assessed the presence and size of GA in digital color photographs (CPs) and fluorescein angiograms (FAs) taken at baseline and at years 1, 2, and 5.
The main outcome measures were presence of GA and its growth rate. Annual change in the square root of the total area of GA was the measure of growth. Multivariate linear mixed models, including baseline demographic, treatment, and ocular characteristics on CP/FA and optical coherence tomography (OCT) were used to analyze candidate risk factors.
Among the 1,011 participants who did not have GA at baseline and had follow-up images gradable for GA, the cumulative incidence was 12% at 1 year; 17% at 2 years; and 38% at 5 years. The authors found that the following baseline characteristics were associated with higher risk of developing GA: older age, hypercholesterolemia, worse visual acuity, larger choroidal neovascularization area, retinal angiomatous proliferation lesion, GA in the fellow eye, and intraretinal fluid. In contrast, a thicker subretinal tissue complex and the presence of subretinal fluid were associated with lower risk of developing GA.
The overall GA growth rate was 0.33 mm/year (standard error, 0.02 mm/year). Eyes treated with ranibizumab in the first 2 years of the clinical trial had a higher growth rate than those treated with bevacizumab (adjusted growth rate, 0.38 vs. 0.28 mm/year). GA in the fellow eye, hemorrhage, and absence of sub-RPE fluid at baseline were associated with a higher growth rate.
In conclusion, development of GA is common 5 years after initiation of therapy. In considering risk factors, the authors noted that the presence of subretinal fluid is associated with a lower incidence of GA, and the presence of sub-RPE fluid is associated with slower growth of GA. They stated that further research is needed to assess whether complete eradication of fluid under the retina should or should not be a goal for anti-VEGF therapy.
The original article can be found here.