To determine age- and sex-specific prevalence and incidence of demyelinating optic neuritis and the risk of multiple sclerosis (MS) in pediatric and adult populations in South Korea, researchers conducted a nationwide, retrospective study using data from the Korean National Health Claims database from 2010 to 2016. The study found that the estimated cumulative incidence of demyelinating optic neuritis was 12.51 per 100,000 people in the entire population, and the incidence was 3.2 times higher in adults than in children. The estimated annual incidence was 1.04 per 100,000 pediatric individuals and 3.29 per 100,000 adults.

Among 44,700,564 individuals, the researchers identified optic neuritis in 531 patients ages 14 or younger and 7,183 adults between the ages of 15 and 65. Patients with optic neuritis had a subsequent diagnosis of idiopathic, MS, neuromyelitis optica (NMO) or acute disseminated encephalomyelitis. The study observed peak incidence of optic neuritis between the ages of 10 and 14 in the pediatric population, and between ages 30 and 34, as well as ages 50 and 54, in the adult population. The researchers found the incidence of optic neuritis and subsequent risk of MS in the pediatric population was comparable to those reported in western countries, was lower in the adult population than in western countries.

The study’s findings also estimated the overall MS conversion rate in the South Korean population to be 10.6%, with the conversion rate being 13.8% in the pediatric population and 11.4% in the adult population. The researchers noted that nearly all patients with acute optic neuritis were hospitalized and given high-dose methylprednisolone treatment. Other treatment modalities included plasmapheresis in 38% of patients with NMO and interferon-β in 50% of patients with MS. Chronic immunosuppressive agents were used more in patients with NMO than with MS.

The researchers hope their findings will help highlight the social cost of optic neuritis.