Pathologic Myopia and Retinal Neovascularization

New Orleans—An analysis of a claims database in the United States, which covers >25 million lives annually, found that the incidence of pathologic myopia (PM) was 2.75 per 10,000 individuals in 2011, while the prevalence of PM was 9.64 per 10,000 individuals. Of the patients who had PM, 3.77% were eventually diagnosed with retinal neovascularization (RNV), a vision-threatening complication of choroidal neovascularization (CNV).

Results were presented during a poster session at the ISPOR annual international meeting. The poster was titled Prevalence and Incidence of Pathologic Myopia and Retinal Neovascularization in a US Managed Care Database. The authors noted that the database included only people with commercial insurance, so “caution is required when extrapolating these estimates to the general population.”

Although PM is a leading cause of visual impairment and registered blindness, the condition is poorly understood, and there is a lack of data to analyze, according to the authors. They also noted that there is not much known about CNV, the most common vision-threatening complication of PM. However, previous studies estimated the prevalence of PM was 1% to 3% of people, while the annual incidence of blindness due to PM ranged from 0.8 to 12.6 per 100,000 population. As the disease progresses, approximately 5% to 10% of patients with PM develop CNV.

In this analysis, the authors evaluated data from the Truven MarketScan^® Commercial Claims and Encounters and Medicare Supplemental Databases. They identified cases of PM and RNV using codes in the International Classification of Diseases, Ninth Revision. They noted that they used the code for RNV because there is no code for CNV. The definitions of RNV and CNV are not identical. Thus, the authors said that the estimates may not “accurately reflect the true incidence” of CNV, although they are consistent with estimates from previous studies.

The authors found 10,200 cases of PM and 614 cases of RNV in the people who had PM. Of the people with PM, the mean age was 47.9 years, 62.3% were female, and 46.5% were <50 years of age. Of the people with PM who also had newly diagnosed RNV, the mean age was 52.4 years, 70.5% were female, and 36.5% were <50 years of age.

In addition, of the 45,226,794 individuals in the database in 2011, 43,581 were previously diagnosed with PM, for a prevalence of 9.64 per 100,000 population. However, because the database had a short mean follow-up period of approximately 2 years, the prevalence of PM “may be significantly underestimated,” according to the authors. They also noted, “these prevalence data should therefore be interpreted with caution.”

The incidence of PM was 2.75 (95% confidence interval, 2.70-2.80) per 10,000 population. The incidence and prevalence of PM was twice as high in people who were ≥50 years of age compared with those <50 years of age.

The analysis also found that of the 16,269 people with PM for at least 4 years, 614 were later diagnosed with RNV, for an incidence of 3.77% with a mean follow-up period of 5.8 years. The authors noted the incidence was similar to a previous study in Japan. The incidence of RNV was twice as high in people who were ≥65 years of age compared with those <50 years of age.

This study was supported by funding from Novartis AG.