Incidence and prevalence of immune thrombocytopenia under the copayment waiver policy for pediatric patients in Korea: Data from the National Health Claims Database.

The purpose of this study was to investigate the epidemiology of immune thrombocytopenia (ITP) under the copayment waiver policy for pediatric patients in Korea. The data were collected from the National Health Insurance Claims Database of Korea. ITP was identified based on the diagnostic code D69.38 from the Korean Standard Classification of Diseases. Patients between one and 18 years old, who had at least one health insurance claim for ITP as a final diagnosis, from 1 January 2016, to 31 December 2017, were analyzed. Prevalent cases were defined as patients who used, at least one time, any medical services coded as D69.38. Incident cases were defined as patients who did not use D69.38 coded medical services during the prior year and were newly registered in 2017. The prevalence and incidence of ITP were 24.53 and 13.39 per 100,000 persons. The peak rates were observed in 1-year-old patients. The gender-specific prevalence of ITP was significantly higher in one-year-old males than females. According to the change-point analysis, we found that the prevalence and incidence diminished rapidly at the ages of four and three, respectively. This Korean population-based epidemiological study of ITP provided meaningful insights into the current epidemiology of ITP and demonstrated the implications of interpreting epidemiologic studies to reflect age categorizing and health care system characteristics.