Association Of Circulating Supar With Disease Severity And Clinical Outcomes In Patients With Ards Induced By Intra-Abdominal Infections: A Prospective Observational Study

Background: Soluble urokinase-type plasminogen activator receptor (suPAR) is used as a biomarker for inflammatory factor in various conditions, but its potential role as a biomarker in patients with acute respiratory distress syndrome (ARDS) induced by intra-abdominal infection has not yet been assessed. The aim of the current study was to identify the diagnostic and prognostic value of suPAR in this population. Methods: We performed a 1-year prospective observational study in the general intensive care unit of The Affiliated Hospital of Qingdao University, Qingdao, China, from January 2014 to February 2015. Patients who had acquired ARDS as a result of intra-abdominal infection were enrolled into the study, along with patients with sepsis and healthy control individuals. Clinical parameters were recorded and serum samples were collected, and serum levels of suPAR and other inflammatory markers were determined. ARDS patients were followed for 90 days following hospital discharge. Results: A total of 45 ARDS patients, 47 sepsis patients and 50 healthy control individuals were enrolled. ARDS and sepsis patients showed elevated suPAR serum concentrations compared with healthy volunteers, but there were no significant differences between patients with ARDS and those with sepsis. The value of suPAR in the diagnosis of ARDS was therefore limited. However, suPAR levels were associated with ARDS severity and other disease-severity scores, such as Acute Physiology and Chronic Health Evaluation II and the Simplified Acute Physiology Score II. Further analysis revealed that the suPAR level could predict worse outcomes for ARDS patients, and receiver operating characteristic analyses indicated that a suPAR cut-off value of 310 pg/ml on admission was the best predictor of mortality. Kaplan-Meier survival analysis confirmed these results. Conclusions: This prognostic study indicates that suPAR is a reliable marker of ARDS severity and a strong independent predictor of unfavorable outcomes in patients with intra-abdominal infection. However, its power to discriminate between ARDS and sepsis appears to be limited.