Causes of hospitalization and their impact on the course of fibrosing interstitial lung diseases

Interstitial lung disease (ILD) is a diverse and heterogenous group of chronic lung diseases affecting lung parenchyma and characterized by inflammation followed by pulmonary fibrosis that can progress and lead to hospitalization. The impact of hospitalizations on the clinical course of ILD is not fully understood. The aim was to analyze the causes of hospitalization related to the underlying disease and their relationship with the clinical and functional features of the disease course in patients with fibrosing ILD (f-ILD). Methods. This study was an open comparative non interventional study. We analyzed findings from two groups of patients with f-ILD, who had or did not have hospitalizations due to respiratory reasons during the previous 12 months. Additionally, we analyzed demographic and clinical data, severity of ILD according to Gender, Age, Physiology (GAP) scale, lung function and echocardiographic parameters, physical tolerance in 6-minute walk test (6MWT), and pharmacological therapy. Results. Ninety-five patients with f-ILD were involved in the study. Of them, 37 patients had one to four previous hospitalizations due to respiratory reasons during the previous 12 months, and 58 patients did not have any hospitalizations during this period. Most frequent reasons for hospitalization were progressing or exacerbation of f-ILD, less frequent reasons were community-acquired pneumonia and other respiratory infections, and pulmonary embolism. One third of the patients (n = 29) were hospitalized for elective procedures to verify the diagnosis. Patients with previous hospitalizations had more severe course of f-ILD according to GAP scale, lower parameters of lung function, oxygenation, and physical tolerance and more often were treated with pharmacological agents and supplemental oxygen. Conclusion. Most common reasons for hospitalization of f-ILD patients were progressing or exacerbation of f-ILD and the need in elective procedures to verify the diagnosis. Patients hospitalized for respiratory reasons during the previous 12 months had more severe clinical course of the disease with lower lung function and physical tolerance and more often required pharmacological therapy and supplemental oxygen as compared to the patients who had no hospitalizations in this time interval. Further studies are needed to investigate the prognostic value of hospitalizations in f-ILD.