Urinary intestine fatty acid binding protein is associated with poor outcome of pneumonia patients in intensive care unit

Background: Urinary intestine fatty acid binding protein (U-IFABP) is a biomarker for gut injury. Previous studies showed that enterocyte damage in critically ill patients was common and appeared to be associated with poor prognosis. However, the impact of enterocyte damage on the outcome of critically ill patients with pneumonia has not yet been well investigated. The aim of the study is to evaluate the prognostic value of U-IFABP in critically ill patients with pneumonia. Methods: A prospective observational study was performed in the intensive care unit (ICU) from September 1, 2013 to April 30, 2014. Pneumonia patients were divided into survival and non-survival groups. U-IFABP was measured using enzyme linked immunosorbent assay for 7 consecutive days after admission to ICU and expressed as U-IFABP/urine creatinine ratio. The prognostic value was tested by Receiver Operator Characteristic (ROC) curves and Kaplan-Meier curves. Results: A total of 32 pneumonia patients with endotracheal intubation were enrolled. U-IFABP/Cr levels were significantly higher in non-survivors than in survivors at day 1 (p = 0.033), day 4 (p = 0.018), day 5 (p = 0.008), day 6 (p = 0.006) and day 7 (p = 0.008) after ICU admission. The areas under ROC curve in predicting mortality were 0.755 (Dl), 0.781(D4), 0.812(D5), 0.823(D6), and 0.812 (D7). Moreover, pneumonia patients with day 7 U-IFABP/Cr above the cutoff of 28.9 pg/100 μL had a significantly lower survival rate (p = 0.043). Conclusions: Enterocyte injury was common in critically ill patients with pneumonia. The severity of enterocyte injury, as evidenced by the U-IFABP/Cr, was associated with the patient's mortality. U-IFABP/Cr may serve as a significant prognostic factor for patients with pneumonia admitted to ICU. Further studies with larger populations are needed to verify these issues.