Trends in Hospitalizations of Patients with Idiopathic Inflammatory Myopathies: Long-Term Observational Study, 2010–2024

Background/Objectives: Idiopathic inflammatory myopathies (IIMs) are very rare, chronic, immune-mediated diseases that clinically manifest with myositis symptoms and extramuscular manifestations. The rarity of the disease makes it difficult to conduct double-blind studies, and large population-based studies are needed to improve our knowledge of them. This study aims to analyze the hospitalization rates and trends of IIMs between 2010 and 2024. Additionally, a characterization of the IIM patient population in Poland was conducted.

Methods

A retrospective study using data from the Nationwide General Hospital Morbidity Study (NGHMS) between 2010 and 2024 was conducted. Data included demographic characteristics, principal diagnosis, hospitalization, and in-hospital mortality. Classification in accordance with ICD-10 was applied. A total of 7139 patients were included. Appropriate descriptive analyses, comparative tests, Poisson regression for incidence trends, and logistic regression for mortality predictors were performed, with p < 0.05 considered statistically significant.