Early Age-Related Macular Degeneration Prevalence Is Rising, Late-Stage Is Steady

Although early stage age-related macular degeneration (AMD) has outpaced estimates in the United States, the predictions for patients progressing to late stage disease has met expectations, according to a study published in JAMA Ophthalmology. Investigators reviewed AMD prevalence predictions from a study conducted from 2005 to 2008, and relevant data from 2019 for early and late stage AMD.

The researchers conducted a meta-regression analysis to estimate early- and late-stage AMD overall and by age, race, ethnicity, county, and state. The study included data from the American Community Survey (2019), the National Health and Nutrition Examination Survey (2005-2008), U.S. Centers for Medicare & Medicaid Services claims for fee-for-service beneficiaries (2018), and population-based studies (2004-2016). Data was stratified, when possible, by factors including county, age group, gender, and race and ethnicity. 

The researchers defined early-stage AMD as retinal pigment epithelium (RPE) abnormalities or the presence of drusen that is 125 µm in diameter or larger in either eye. Late-stage AMD was defined as choroidal neovascularization or geographic atrophy, or both, in either eye. The main outcome measure was the prevalence of early- and late-stage manifestations of AMD.

The study authors estimate that 18.34 million people who are 40 years or older (95% CI 15.30-22.03) have early-stage AMD, which corresponds to a crude prevalence rate of 11.64% (95% CI 9.71-13.98). “Applying the same definition of early-stage AMD to the 2005 to 2008 NHANES data results in a prevalence of 12.7% for noninstitutionalized individuals 50 years or older before adjusting for missing data or additional modeling. Forecasting estimates predicted a 2020 prevalence of early-stage AMD of 12.0% among persons 50 years or older. Our current estimates are slightly higher than these earlier projections when accounting for the inclusion of individuals 40 years or older.”

For late-stage AMD, the researchers estimated 1.49 million people 40 years and older (95% CI 0.97-2.15), corresponding to a crude prevalence rate of 0.94% (95% CI 0.62-1.36). “Using 2005 to 2008 NHANES data, Klein et al estimated a prevalence rate of late AMD of 0.8% among people 40 years or older, but that estimate excluded adjustments for people living in institutionalized settings or increased aging of the US population from 2008 to 2019,” according to the study.

The researchers highlight the fact that substantial variation in the prevalence of both early- and late-stage AMD was identified at the state and county level, even after accounting for differences in demographics. Still, their meta-analysis returned a high number of combined early- and late-stage AMD patients.

“We estimate that 19.83 million individuals in the US were living with some form of AMD in 2019,” according to the study. The researchers also report that prior research predicted declines in AMD prevalence due to “reductions in smoking and improvements in blood pressure control.”

Study limitations include its analysis of older data, including data from NHANES and PBS, and the use of imputation methods to account for missing data. 

Disclosure: Some of the study’s authors have declared affiliations with the biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.