Treatment Patterns of Oral Glucocorticoids in Patients with IgG4-Related Disease: A Real-World Analysis based on a Japanese Claims Database

Objectives To describe the prescribing patterns of oral glucocorticoid and evaluate flares and glucocorticoid-related complications in patients with immunoglobulin G4-related disease. Methods This retrospective observational study used a Japanese hospital claims database. Patients with a prescription for oral glucocorticoids, a diagnosis of immunoglobulin G4-related disease, and having at least two immunoglobulin G4 measurement tests were included. The index date was defined as the first oral glucocorticoid prescription recorded in the database (Day 0). Patients were followed for up to Day 1460 (4 years). Results The study included 3,167 patients. The mean dose of oral glucocorticoid was 28.76, 10.71, and 4.12 mg/day on Day 0, 90, and 1095, respectively. At Day 1460, 66.56% of the patients were still receiving oral glucocorticoid therapy and the dose exceeded 5 mg/day in 17.80% of patients. During the follow-up period, 453 patients (14.30%) experienced at least one flare. The incidence rates of hospitalized infections, osteoporotic fractures, and cardiovascular diseases, defined as serious glucocorticoid complications, were 7.46, 0.61, and 1.61 per 100 person-years, respectively. Conclusions Over half of the patients continued glucocorticoid therapy at 4 years. Glucocorticoid withdrawal strategies could be associated with reducing the long-term glucocorticoid-related toxicity in patients with immunoglobulin G4-related disease.