OBJECTIVES: The epidemiology of pathologic myopia (PM), an important cause of visual impairment worldwide, is poorly understood. This study analyzed data from a large US claims database to estimate the prevalence and incidence of PM and PM + retinal neovascularization (RNV).
METHODS: Data were drawn from the MarketScan® Commercial Claims and Encounters database and Medicare Supplemental and Coordination of Benefits in the USA. ICD9 diagnostic codes for PM (360.21) and both PM + RNV (362.16) were used to identify cases; use of the diagnostic code on at least one occasion was required. A 1-year disease-free period was required for a diagnosis to be considered an incident case.
RESULTS: MarketScan covered 45,226,794 patients in 2011; 43,581 and 1,781 prevalent cases of PM and PM + RNV were identified, representing a prevalence of 9.64 (95% CI: 9.55–9.73) and 0.39 (95% CI: 0.38–0.41) per 10,000 population, respectively. Incidence per 10,000 persons in 2011 was 2.75 (95% CI: 2.70–2.80) for PM and 0.09 (95% CI: 0.08–0.10) for PM + RNV. Subjects with incident PM had a mean age of 47.9±18.5 years, 46.5% were under 50 years old, and 62.3% were females, whereas subjects with PM + RNV had a mean age of 55.1±14.5, 30.3% were younger than 50 years old, and 71.1% were females.
CONCLUSIONS: Prevalence and incidence estimates of PM among the commercially insured US population in 2011 were approximately 9.6 and 2.7 per 10,000 persons, respectively. PM+RNV represents approximately 3-4% of patients with PM. Using only one diagnostic code to identify cases may overestimate prevalence and incidence as there is potential to include some diagnoses that would later be ruled out as true cases. Both PM and PM+RNV are often diagnosed in individuals younger than 50 years of age and the majority of patients are female.
