The factors influencing differences in adoption of anti-VEGF injections are still poorly characterized, and trends in national anti-VEGF use and associated costs have only been documented until 2015 in the population insured by Medicare.
A recent study characterized trends in use of and expenditure for the intravitreal injection of anti-VEGF agents aflibercept, ranibizumab and bevacizumab among the population enrolled from 2014 to 2019.1 In this period, 17,588,995 intravitreal injection claims were filed by 4,218 U.S. ophthalmologists. Medicare costs for anti-VEGF injections increased from $2.51 billion in 2014 to $4.02 billion in 2019.
Increased state-level ophthalmologist availability and incremental increases in average reimbursement amounts were found to be significantly associated with a 6.8-fold variation in 2019 overall anti-VEGF injection rates across states. The researchers found a 7.3-fold difference in aflibercept use, a 231.9-fold difference in ranibizumab injection rate and a 37.9-fold difference in bevacizumab injection rates across all 50 United States and the District of Columbia.
“While the determinants of regional variation are multifactorial, we found access to injecting ophthalmologists to be one factor significantly associated with this variation,” the authors wrote in their paper. “States with a higher density of injecting physicians were associated with a higher anti-VEGF injection rate, as well as higher aflibercept and bevacizumab agent-specific injection rates.”
Study co-author Sarishka Desai, a medical student at the University of Connecticut, also comments on an interesting interaction between reimbursement and injection rate.
“In our study, increased reimbursement was also found to be minimally associated with overall anti-VEGF injection rate; a $1 increase in reimbursement rate was associated with 3.3 additional injections per 100,000 beneficiaries,” she says.
She notes that this effect was inconsistent across individual anti-VEGF agents. “We found a $1 increase in reimbursement rate to be negatively associated with bevacizumab injection rate,” she says. “We believe this may be due to increased use of aflibercept and/or ranibizumab–it’s important to remember the market for anti-VEGF injections is a zero-sum game. We hypothesize practitioners in states with higher reimbursements have higher practice expenses and patients with greater access to care, which may increase aflibercept injection rates and decrease bevacizumab injection rates as a result. However, in our study we cannot draw any causal associations, and further research is needed.”
Population-adjusted aflibercept injection rate increased 138 percent from 2014 to 2019, while ranibizumab injection rate marginally increased and bevacizumab injection rate slightly decreased. “Though aflibercept was initially approved for wet AMD, expanding indications (e.g., proliferative diabetic retinopathy, diabetic macular edema) in the management of ophthalmic disease may partially explain the nationwide increase in injection rate,” the authors noted.
“Additionally,” they say, “the ability to extend patients for a longer period between injections may also explain an increase in aflibercept injection rates.”
“Future studies are warranted to better elucidate whether the observed gaps in state-level injection rates result from physician-specific characteristics, regional characteristics or payments provided by the pharmaceutical industry (e.g., consultation, education, travel, food and beverage),” they added. “This will help reveal the most appropriate policies which may help decrease observed disparities in injection rates unaccounted for by the distribution of eye disease burden.”
1. Desai S, Sekimetsu S, Rossin EJ, Zebardast N. Trends in anti-vascular endothelial growth factor original Medicare part B claims in the United States, 2014-2019. Ophthalmic Epidemiol. February 5, 2024. [Epub ahead of print].
Pachydrusen in AMD Eyes Raises Risk of MNV
A new study explored associations between the risk of progression to advanced AMD and the type of drusen present, if any. Of particular interest was a recently identified type called pachydrusen, which have well-defined margins with an irregular outer contour and which occur in isolation or in groups of a few at the posterior pole, the researchers explained in their paper for Scientific Reports.1
Many aspects of pachydrusen, including the long-term prognosis and risk factors for progression to advanced AMD remain unclear, due to a lack of a longitudinal study. Researchers in South Korea investigated the occurrence of advanced AMD and risk factors for progression to advanced AMD in eyes with pachydrusen. They found that age and macular pigmentary changes were risk factors for the progression to wet AMD in eyes with pachydrusen. However, the number of macular pachydrusen and the presence of macular neovascularization in the fellow eye didn’t show a statistically significant relationship with MNV development.
This retrospective longitudinal study included 248 eyes of 156 patients with pachydrusen without advanced age-related macular degeneration at baseline. The mean age at baseline was 65.4 years, and the mean follow-up duration was 6.4 years.
The mean total number of pachydrusen and macular pachydrusen were 4.1 and 2.27 per eye, respectively. Pachydrusen was accompanied by other types of drusen in 4.8 percent of eyes at baseline. During follow-up, MNVs occurred in 2.8 percent (seven eyes), which included polypoidal choroidal vasculopathy in six eyes; however, no geographic atrophy occurred.
The cumulative incidence curves differed significantly based on the presence of macular pigmentary changes. In eyes with pachydrusen, the 10-year cumulative incidence of macular neovascularization was significantly higher when macular pigmentary changes were present than when they were absent (17.39 percent vs. 0.57 percent). In the analysis of MNV development according to the age at baseline, those aged older than 67 years showed a higher frequency of MNV development than did those aged 67 years or younger, although they had a short period of follow-up.
“If pachydrusen eyes have a risk profile for progression to advanced age-related macular degeneration that is different from that of AMD eyes with drusen other than pachydrusen, the current advanced AMD risk prediction methods may not work in eyes with pachydrusen,” the researchers wrote in their paper.
“We believe that the current age-related macular degeneration classification should be updated to distinguish drusen types if pachydrusen has a different risk profile from that of other drusen,” they concluded. “Further studies with larger sample sizes should be performed to confirm the results of this study.” RS
1. Nam SW, Noh H, Yoon JM, Ham DI. Advanced age-related macular degeneration and risk factors in eyes with pachydrusen. Sci Rep. 2024;14:1:6132.
