Abstract
While age-related macular degeneration (AMD) poses an important personal and public health burden, comparing epidemiological studies on AMD is hampered by differing approaches to classify AMD. In our AugUR study survey, recruiting residents from in/around Regensburg, Germany, aged 70+, we analyzed the AMD status derived from color fundus images applying two different classification systems. Based on 1,040 participants with gradable fundus images for at least one eye, we show that including individuals with only one gradable eye (n = 155) underestimates AMD prevalence and we provide a correction procedure. Bias-corrected and standardized to the Bavarian population, late AMD prevalence is 7.3% (95% confidence interval = [5.4; 9.4]). We find substantially different prevalence estimates for “early/intermediate AMD” depending on the classification system: 45.3% (95%-CI = [41.8; 48.7]) applying the Clinical Classification (early/intermediate AMD) or 17.1% (95%-CI = [14.6; 19.7]) applying the Three Continent AMD Consortium Severity Scale (mild/moderate/severe early AMD). We thus provide a first effort to grade AMD in a complete study with different classification systems, a first approach for bias-correction from individuals with only one gradable eye, and the first AMD prevalence estimates from a German elderly population. Our results underscore substantial differences for early/intermediate AMD prevalence estimates between classification systems and an urgent need for harmonization.
Highlights
Age-related macular degeneration (AMD) is a degenerative disorder affecting the choroid/retinal pigment epithelium (RPE)/photoreceptor complex of the central retina and represents the leading cause of central vision loss in the elderly populations of industrialised countries[1,2]
While the definition of late age-related macular degeneration (AMD) is reasonably homogeneous across classification systems, these systems differ substantially in their approach to classify early/intermediate AMD: utilized systems include the Wisconsin age-related maculopathy grading system (WARMGS)[5], the Rotterdam Study classification[6], or two AMD severity
A further issue that can induce misclassification and between-study differences is the inclusion of participants with only one gradable eye, which is common practice in ophthalmic epidemiology[5,7,8,9,10,11]: defining a person’s AMD status as the AMD status in the worse eye implies a larger probability of AMD “diagnosis” when there are gradable images for both eyes compared to only one eye
Summary
Age-related macular degeneration (AMD) is a degenerative disorder affecting the choroid/retinal pigment epithelium (RPE)/photoreceptor complex of the central retina and represents the leading cause of central vision loss in the elderly populations of industrialised countries[1,2]. While the definition of late AMD is reasonably homogeneous across classification systems, these systems differ substantially in their approach to classify early/intermediate AMD: utilized systems include the Wisconsin age-related maculopathy grading system (WARMGS)[5], the Rotterdam Study classification[6], or two AMD severity www.nature.com/scientificreports/. Data from Germany or Central Europe on late and early/intermediate AMD prevalence is limited, as emphasized by the German Ophthalmology Society[12]: the only two studies from Germany, the Gutenberg Health Study (GHS, n = 4,340)[13] and the Cooperative Health Research in the Augsburg Region (KORA) study (n = 2,546)[11], provide estimates in a general population aged 35–74 or 25–75 years, respectively, and include as few as nine or six late AMD patients, respectively[11,13]. A recent meta-analysis of 39 population-based studies worldwide includes only one population-based study from Central Europe (the Rotterdam Study)[14]
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