Prognostic roles of KL‐6 in disease severity and lung injury in COVID‐19 patients: A longitudinal retrospective analysis
Kai Deng, Qinghong Fan, Yanhong Yang, Xizi Deng, Ruiying He, Yizhou Tan, Yun Lan, Xilong Deng, Yuejun Pan, Yaping Wang, Yujuan Guan, Huiyuan Liu, Fengjuan Chen, Xiaoneng Mo, Xinghua Tan, Chun Luo, Xueliang Wen, Ying Liu, Jinxin Liu, Lieguang Zhang, Xiaoping Tang, Fengyu Hu, Feng Li
Abstract
To investigate the dynamic changes of Krebs von den Lungen-6 (KL-6) among patients with coronavirus disease 2019 (COVID-19) and the role of KL-6 as a noninvasive biomarker for predicting long-term lung injury, the clinical information and laboratory tests of 166 COVID-19 patients were collected, and a correlation analysis between KL-6 and other parameters was conducted. There were 17 (10.2%, 17/166) severe/critical and 149 (89.8%, 149/166) mild COVID-19 patients in our cohort. Serum KL-6 was significantly higher in severe/critical COVID-19 patients than in mild patients (median 898.0 vs. 451.2 U/ml, p < .001). KL-6 was next confirmed to be a sensitive and specific biomarker for distinguishing mild and severe/critical patients and correlate to computed tomography lung lesions areas. Serum KL-6 concentration during the follow-up period (>100 days postonset) was well correlated to those concentrations within 10 days postonset (Pearson r = .867, p < .001), indicating the prognostic value of KL-6 levels in predicting lung injury after discharge. Finally, elevated KL-6 was found to be significantly correlated to coagulation disorders, and T cells subsets dysfunctions. In summary, serum KL-6 is a biomarker for assessing COVID-19 severity and predicting the prognosis of lung injury of discharged patients.