Abstract
BACKGROUND: Interstitial lung disease (ILD) in inflammatory rheumatic diseases (IRD) is of great importance in the diagnostics and treatment. Due to the often complex and severe courses, inpatient care is often necessary. New data are needed regarding the frequency of lung involvement in general and the development of the proportion of inpatients in Germany. METHODS: A retrospective analysis of the inpatient diagnoses published by the Federal Statistical Office according to the International Classification of Diseases (ICD-10) from 2005 to 2023 in Germany was carried out. A total of 11 main rheumatological diagnoses were analyzed, in particular rheumatoid arthritis (RA, M05, M06), connective tissue disease (M32-M35), ANCA-associated vasculitis (M30.1, M31.3, M31.7) and axial spondylarthritis (M45). The frequency of additionally coded secondary diagnoses of lung involvement (J84.1, J84.8, J84.9, J99.0*, J99.1*) was presented over a total observational period of 19 years. RESULTS: There were between 50,540 and 64,004 inpatient stays per year with one of the main rheumatological diagnoses examined. The number rose to as high as 64,000 from 2005 to 2019, collapsed in 2020-2022 and stood at 54,077 in 2023. The proportion with coded lung involvement rose from 7% (3524 in 2005) to 17% (9398 in 2023). Lung involvement was most common in granulomatosis with polyangiitis (46%), systemic sclerosis (44%), Sjögren's syndrome (27%) and Sharp's syndrome (24%). In seropositive RA 8% and in seronegative RA 1% had lung involvement (data from 2023). DISCUSSION: During the period under study, the number of inpatient stays with a main rheumatological diagnosis in Germany increased, with a slump during the SARS-CoV 2 pandemic. The continuously increasing proportion of patients with lung involvement indicates the inpatient interdisciplinary care needs of this growing rheumatological patient group.