Clinical characteristics and progression of Geographic Atrophy in a Japanese population

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A Japanese research team reported that some characteristics of Asian patients with geography atrophy (GA) associated with age-related macular degeneration (AMD) differ from the characteristics of White populations. They believe that these phenotypic differences in GA should be considered in different ethnicities because they may have implications in research and in interventions to slow progression of GA,¹ according to the lead author Yukiko Sato, MD, from the Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan.

However, the researchers pointed out, little information is available on the clinical characteristics of GA in Asian populations.^2-4 It is essential to accumulate clinical data on GA, especially regarding the GA progression rate and factors that modify this progression in Asian populations, to better understand the differences in GA in different ethnicities to ensure that appropriate and effective treatments can be delivered to Asian patients.”

This retrospective, multicenter, observational study examined Japanese patients with GA to determine the clinical characteristics and GA progression rate associated with AMD in an Asian population.

Patients from 6 university hospitals in Japan were included. Of 173 study eyes of 173 Japanese patients who were enrolled, 101 eyes from 101 patients were included in the follow-up group. All patients were 50 years or older and had definite GA associated with AMD in at least 1 eye.

The main outcomes were the clinical characteristics of GA and the GA progression rate.

The researchers measured the GA area semiautomatically using fundus autofluorescence (FAF) images. The follow-up group was evaluated for longer than 6 months with FAF images, and the GA progression rate was calculated using 2 methods: the mm2 per year and the mm per year using the square-root transformation (SQRT) strategy.

Results of GA analysis

The mean patient age was 76.8 ± 8.8 years; 109 (63.0%) patients were men. Sixty-two (35.8%) patients had bilateral GA (mean GA area, 3.06 ± 4.00 mm2 (1.44 ± 1.00 mm, using SQRT). Thirty-eight eyes (22.0%) were classified with pachychoroid GA. Drusen and reticular pseudodrusen were detected in 115 (66.5%) and 73 (42.2%) eyes, respectively. The mean subfoveal choroidal thickness was 194.7 ± 105.5 μm.

The 101 patients were followed for 46.2 ± 28.9 months; the mean GA progression rate was 1.01 ± 1.09 mm2 per year (0.23 ± 0.18 mm/year using SQRT). Multivariable analysis showed the baseline GA area (SQRT, P = 0.002) and the presence of reticular pseudodrusen (P < 0.001) were associated significantly associated with a greater GA progression rate (SQRT), the investigators reported.

In commenting on their findings, the researchers said, “Certain clinical characteristics of GA in Asian populations may differ from those in White populations. Asian patients with GA showed male dominance and a relatively thicker choroid than White patients. There was a group with GA without drusen but with features of pachychoroid. The GA progression rate in this Asian population was relatively lower than that in White populations. Large GA and reticular pseudodrusen were associated with a greater GA progression rate.”

They advised that researchers consider the differences in the GA phenotypes in different ethnicities because these differences may have implications when researching GA and considering interventions to slow GA progression.

References:

1. Sato Y, Ueda-Arakawa N, Takahashi A, et al. Clinical characteristics and progression of geographic atrophy in a Japanese population. Ophthalmol Retina. 2023;7:901-909. DOI:https://doi.org/10.1016/j.oret.2023.06.004

2. Rim TH, Kawasaki R, Tham YC, et al. Prevalence and pattern of geographic atrophy in Asia: the Asian eye epidemiology consortium. Ophthalmology. 2020;127:1371–1371.

3. Lee JY, Lee DH, Lee JY, Yoon YH. Correlation between subfoveal choroidal thickness and the severity or progression of nonexudative age-related macular degeneration. Invest Ophthalmol Vis Sci. 2013;54:7812-7818.

4. Jeong YJ, Hong IH, Chung JK, et al. Predictors for the progression of geographic atrophy in patients with age-related macular degeneration: fundus autofluorescence study with modified fundus camera. Eye (Lond).2014;28:209-218.