Analysis of the Incidence and Diagnostic Pattern of Langerhans Cell Histiocytosis from the Population-Wide Healthcare Database in Korea

• Published in: Blood 2019-11, Vol.134 (Supplement_1), p.4866-4866
• Main Authors: Kim, Hyery, Kim, Ye-Jee, Shin, Juhee, MIN, Soyoon, Kang, Sung Han, Suh, Jin Kyung, Koh, Kyung-Nam, Im, Ho Joon, Seo, Jong Jin
• Format: Article
• Language: English
• ISSN: 0006-4971; 1528-0020
• DOI: 10.1182/blood-2019-131531

Introduction Langerhans cell histiocytosis (LCH) is a rare disease involving clonal proliferation of Langerhans cells. The reported incidence of LCH ranges from 0.5-5.4 cases per million persons per year, according to the prospective registry-based reports. However, due to the rarity of the disease and the limitation of prospective registries, the comprehensive understanding of nation-wide epidemiology has been limited. This study aimed to analyze the incidence by age and diagnostic patterns of LCH using the population-wide healthcare database in Korea. Methods The claims data of the Health Insurance Review and Assessment (HIRA) contain information of 46 million patients per year, which accounts for about 95% of the total population of South Korea. The data include information regarding diagnoses, hospitalization, and prescription drugs. Since 2005, the “National cancer registration and reimbursement program” has been implemented, which reimburse for 90% of the medical expenses of patients with malignant diseases, including LCH. Therefore, all the patients with LCH have been registered in the database after a definite diagnosis. From the HIRA open data source, we extracted a claim data of patients corresponding to diagnosis codes of C95.0 (Multifocal and multisystemic -disseminated LCH), C96.5 (Multifocal and unisystemic LCH), or C96.6 (Unifocal LCH) during the period of 2010-2017. Data for 2010-2011 was used as a reference for overlapping patients, and the actual analysis was conducted with data from 2012 to 2017. Results During the period, a total of 59,929 insurance statements were issued, and 53,446 statements with only one identical diagnostic code and confirmative workups were selected for final analysis. The total incidence cases during the period of 2012 to 2017 were 899 cases, and the average number of the annual incidence was 150 cases. The incidence was 3.0 cases per million persons per year. There was a male predominance with a male-to-female ratio of 1.63:1 (558 cases:341 cases) in a whole cohort. For the detailed diagnosis codes, C96.6 was the most frequent as 93.4%, followed by C96.0 as 4.9%, and C96.5 as 1.7%. The average age at diagnosis was 26.6 years (range, 0.2~87 years) in all incidence cases, and 26.6 years for C96.0 group, 29.5 years for C96.5 group, and 25.9 years for C96.6 group, respectively. When patients were grouped by age at diagnosis, the age group of 0-4 years showed the highest annual incidence of 17.9 cases per million, fo