Abstract Background Corticosteroid-based immunosuppressive therapy is the cornerstone of treatment for cardiac sarcoidosis (CS), aimed at preventing severe adverse events including death, heart failure and lethal arrhythmic events. Nevertheless, data on the optimal initial dosing, appropriate tapering schedules, suitable maintenance dosages, and the recurrence rates among patients are insufficient. Purpose This study sought to scrutinize real-world data on corticosteroid therapy regimen for CS and to reassess optimal treatment protocols. Methods From the Japanese Diagnosis Procedure Combination database, 6,282 patients with hospitalized CS were identified between 2012 and 2022. Among them, 3,067 CS patients who were initiated on corticosteroid therapy during hospitalization were analyzed. We examined the baseline patient characteristics and treatment strategies for corticosteroid therapy, including starting dose, tapering period, maintenance dose, and their correlation with the onset of adverse events. Results The cohort had a mean age was 63±11 years, and 1,256 patients (41.0 %) were female. The starting dose of corticosteroids was 30.3±6.9 mg, with 88.6% of patients receiving a dose of ≧30 mg/day. The doses of corticosteroids at 30, 60, 90, 120, 150 and 180 days post-discharge were 21.4±9.8, 15.7±6.9, 12.2±5.7, 10.4±5.0, 9.3±4.5 and 9.0±4.6 mg, respectively. By day 180, 83.7% of the patients were maintained on ≦10 mg/day. However, 17.1 % of patients required an increase in corticosteroid dosage during the tapering course, primarily due to exacerbation of sarcoidosis. When analyzing only the group without corticosteroid escalation up to 180 days post-discharge, the average corticosteroid dose was 8.7±3.8 mg, with 95.3% of patients on ≦10 mg/day. We observed 965 re-hospitalization (31.5 %) during follow-up, with 58.8% of these patients having corticosteroid escalation to ≧30 mg, and 12.8% of patients received second-line immunosuppressive therapy, such as methotrexate. Conclusion The majority of CS patients were initiated on a corticosteroid regimen of 30 mg/day, which was subsequently tapered to below 10 mg/day by day 180. However, non-negligible number of patients experienced clinical events or relapse, underscoring the necessity for vigilant follow-up during corticosteroid therapy.Figure