The value of KL-6 in the diagnosis and assessment of interstitial lung disease.

OBJECTIVE:To investigate the value of Krebs von den Lungen-6 (KL-6) in the diagnosis and activity assessment of interstitial lung disease (ILD). METHODS:The data of 69 ILD patients admitted to our hospital from January 2018 to January 2020 were analyzed retrospectively, and they were included in the ILD group. In addition, 69 patients with connective tissue disease (CTD) admitted to our hospital during the same period were selected and included in the non-ILD (NILD) group. The lung function, pulmonary imaging scores, and KL-6 expression levels were compared between the two groups. The patients in the ILD group were divided into two subgroups: the inactive group and the active group. The pulmonary function, pulmonary imaging scores, and the KL-6 expression levels of the patients in the two subgroups were compared. The value of KL-6 in the diagnosis and the ILD activity evaluation were analyzed. RESULTS:The FEV1, FVC, and DLCO levels in the LID group were lower than they were in the NLID group (P<0.05). The LUS and Warrick scores in the LID group were higher than they were in the NLID group (P<0.05). The FEV1, FVC, and DLCO levels in the active group were lower than they were in the inactive group (P<0.05). The LUS and Warrick scores in the active group were higher than they were in the NLID group (P<0.05). The patients' serum KL-6 levels in the ILD group were higher than they were in the NILD group (P<0.05), and the patients' serum KL-6 levels in the ILD group were higher than they were in the inactive group (P<0.05). The Youden's index of serum KL-6 for the diagnosis of ILD was 421.775 U/ml and the sensitivity and specificity of the serum KL-6 were 91.304% and 95.652%, respectively, showing a high diagnostic value (P<0.05). The Youden's index of the serum KL-6 levels for the evaluation of the ILD activity was den Lungen-6 (KL-, with a sensitivity of 60.976% and a specificity of 100%, showing a moderate evaluation value (P<0.05). CONCLUSION:KL-6 has a high value in the diagnosis of interstitial lung disease, and a moderate value in the assessment of interstitial lung disease activity.