A possibility of pulmonary intravascular coagulopathy in acute exacerbation of interstitial lung diseases: a retrospective cohort study

Background Acute exacerbation (AE) of interstitial lung disease (ILD) is a life-threatening condition that can cause idiopathic pulmonary fibrosis (IPF) and non-IPF. One of the causes of the poor prognostic outcomes of AE-ILD is believed to be the coagulation cascade due to tissue damage. We investigated whether coagulopathy in patients with AE-ILD occurred locally in the lungs using laboratory data. Methods A total of 81 patients with chronic and acute ILD were enrolled in this study. A retrospective analysis was performed in two groups: a chronic ILD group comprising 63 outpatients and an acute ILD group comprising 18 inpatients diagnosed with AE-ILD. Results ROC analysis of SP-D, TAT, D-dimer, and PIC levels indicated that these four markers might be good diagnostic markers of AE-ILD. Spearman’s correlation coefficient analysis revealed a positive correlation between SP-D and TAT (r=0.711, p=0.004), D-dimer (r=0.626, p=0.011), and PIC (r=0.741, p=0.002). Multiple regression analysis performed for TAT values with age, male sex, baseline use of anticoagulant drugs, acute ILD, IL-6 value, and SP-D value showed that the model could explain 57.6% of TAT values (R2 = 0.609, adjusted R2 = 0.576). In addition, the baseline use of anticoagulant drugs (β=-6.8092, pConclusion SP-D, TAT, D-dimer, and PIC may be useful markers for diagnosing AE-ILD. Based on these four serum markers, the present study suggests that coagulopathy caused by AE-ILD may occur locally in the lungs.