Size and Growth of Geographic Atrophy During 5 Years of Follow Up in the Comparison of Age-related Macular Degeneration Treatments Trials (CATT)

Abstract

Purpose : To quantify the size and growth rate of geographic atrophy (GA) during 5 years of follow up among patients in the CATT.

Methods : 1185 CATT participants were randomly assigned to ranibizumab or bevacizumab treatment and to a 2-year monthly or PRN injection dosing regimen, or monthly injections for 1 year and PRN injections the following year. Patients were released from protocol treatment at 2 years and recalled for examination at approximately 5 years.
Two graders masked to treatment measured total GA size in digital color photographs (CP) and fluorescein angiograms (FA) taken at baseline, Years 1, 2 and 5 using Image J; differences were adjudicated. 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 OCT as candidate risk factors were used to estimate adjusted growth rates, standard errors (SE), and 95% confidence intervals.

Results : Among 529 patients followed for 5 years with gradable photographs, 214 (40.5%) had GA at Year 5, and 112 had at least 2 GA measurements at different time points allowing the estimation of growth rates.

Mean area of prevalent GA at baseline was 1.93 (0.36, SE) mm². Mean area of incident GA at the time of first detection at Years 1, 2, and 5 were 1.89 (0.40), 2.86 (0.95) and 7.09 (0.85) mm². Although GA size increased over time by a mean of 0.29 (0.02) mm/year, the GA growth rate generally decreased from years 1 to 5 (Table 1).

Multivariate analysis results (Table 2) showed that predominantly classic lesions were associated with higher growth rate than occult only lesions (0.38 vs. 0.24 mm/year, p=0.04). Eyes without sub-RPE fluid had higher GA growth than eyes with sub-RPE fluid away from the fovea or subfoveal (0.35, 0.31 and 0.21 mm/year respectively p=0.02). There was no significant difference in GA growth between GA associated with the CNV lesion and GA that was outside the CNV lesion (0.28 vs. 0.30 mm/year, p=0.91), and between the two drugs (p=0.12) and three dosing regimens (p=0.89) that patients received during the first two years of the study (Table 2).

Conclusions : In this cohort of patients followed for approximately 5 years higher GA growth was observed in eyes with predominantly classic lesions and eyes with no sub-RPE fluid at baseline.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.

 

Table 1

 

Table 2