ABSTRACT
Background: Krebs von den Lungen-6 (KL-6) is a mucin glycoprotein mainly produced on the surface of alveolar type 2 epithelial cells. Some case-control studies comparing healty subjects to COVID-19 patients in different stages of severity have documented that serum KL-6 levels predict COVID-19 severity and poor clinical outcomes. However, the relevance of KL-6 in patients with severe and critical COVID-19 have not fully elucidated. Method(s): Retrospective data from consecutive severe to critical COVID-19 patients were collected at UOC Clinical Pnuemologica "Vanvitelli", A.O. dei Colli, Naples, Italy. Study included patients with a positive rhinopharyngeal swab for SARS-COV-2 RNA with severe or critical COVID-19. Result(s): Study population characteristics are reported in Table 1. Among 87 patients 24 had poor outcomes (IOT or death). Median KL-6 value in survivors was significantly lower when compared with patients dead or intubated (530 U/mL versus 1069 U/mL p<0.001). KL-6 was correlated with BMI (r: 0.279, p:0.009), LUS Score (r: 0.429, p<0.001), Chung Score (r: 0.390, p<0.001). KL-6 was associated with risk of death or IOT after adjusting for gender, BMI, Charlson Index, Chung Score, and P/F (OR 1.003 95%IC 1.001-1.004, p <0.001). Serum KL-6 value of 968 has a sensivity of 79.2%, specificity of 87.1%, PPV 70.4%, NPV 91.5%, AUC: O.85 for risk of death or IOT (Figure 1). Conclusion(s): The presented research highlights the relevance of serum KL-6 in severe to critical COVID-19 patients in predicting the risk of death or IOT.