Primary immune thrombocytopenia in Italy: epidemiology, management pathways, and the clinical–economic impact of corticosteroids

BACKGROUND/OBJECTIVES: Primary immune thrombocytopenia (ITP) is a rare autoimmune disease characterized by low platelet count. Corticosteroids (CS) are the first-line treatment (1 L), although prolonged use is discouraged due to associated adverse events. This study aimed to estimate the ITP epidemiology, management, and the CS clinical and economic impact in Italy. METHODS: A retrospective observational analysis was conducted using administrative healthcare databases (∼12 million individuals). ITP patients were identified through disease-specific drugs, hospitalizations, and exemption codes during the inclusion period (January 2018-June 2024). CS treated patients were stratified into cohorts according to CS dose and intensity. Incidence rates of rapid-onset and late-onset CS-related events (CSEs) were estimated, and associations with CS use were assessed using Cox regression models. Direct healthcare costs were estimated, and associations with CS use assessed applying a generalized linear model (GLM). RESULTS: Prevalence (at the end of 2023) and annual incidence (2011-2023) were 33.9 and 3.7 per 100,000 persons, respectively. Overall, 1,993 adult ITP patients were identified; 1,643 were incident patients, and 1,214 received CS as 1 L therapy. Incidence rates of rapid-onset and late-onset CSEs were 768.6 and 210.3 per 1,000 person-year, respectively. High-dose/high-intensity CS therapy compared with low-dose/low-intensity regimens was associated with higher risk of late-onset CSEs (HR = 1.51; 95% CI = 1.18-1.92), and higher healthcare costs (adjusted annual cost difference of €1,803 [95% CI = 299-3,452]). CONCLUSIONS: Compared with low-dose/low-intensity CS regimens, high-dose/high-intensity regimens are associated with increased clinical and economic burden in ITP. Limiting prolonged CS use could minimize late-onset CSEs and associated healthcare resource utilization.