Epidemiological features of immunoglobulin G4‐related sclerosing cholangitis in Japan
Atsushi Tanaka, Mitsuru Mori, Kensuke Kubota, Itaru Naitoh, Takahiro Nakazawa, Hajime Takikawa, Michiaki Unno, Terumi Kamisawa, Shigeyuki Kawa, Kazuichi Okazaki
Abstract
BACKGROUND/PURPOSE: Epidemiological data on immunoglobulin G4-related sclerosing cholangitis (IgG4-SC) are scarce. METHOD: We randomly selected healthcare facilities from a list of all facilities in Japan. The selection rate was determined according to a stratification based on the facility characteristics and scale. We sent questionnaires to the selected facilities enquiring about the number and sex of patients with IgG4-SC in 2018. Among responding facilities, we further inquired about the clinical characteristics of the patients with IgG4-SC. RESULTS: We selected 1180 departments from health centers across Japan. Of them, 532 (45.1%) responded to the questionnaires. The number of reported patients with IgG4-SC was 1045, and the estimated point prevalence was 2.18 (95% confidence interval, 2.13-2.23) per 100 000 population. In addition, we enrolled 1096 patients with IgG4-SC, combining data from previously and newly registered patients. Male patients comprised 79.5% of the population and patients aged 60-80 years had the highest risk for developing the disease. The follow-up period was 5.1 ± 4.0 years and the 5- and 10-year overall survival rates were 95.3% and 89.0%, respectively. CONCLUSIONS: The point prevalence of IgG4-SC was 2.18 per 100 000 population. The epidemiological features were similar to those observed in previous studies.