Urea to Albumin Ratio Is an Excellent Predictor of Death in Patients With Complicated Intra-Abdominal Infections

The urea to albumin ratio (UAR) has shown a prognostic value in various clinical settings, however, no study has yet investigated its ability to predict outcome in complicated intra-abdominal infections (cIAIs). Therefore, our aim was to evaluate the association between UAR and mortality in such patients. A single-center prospective study including 62 patients with cIAIs was performed at a University Hospital Stara Zagora for the period November 2018 to August 2021. Various routine laboratory and clinical parameters were recorded before surgery and on post-operative day 3. We used serum levels of urea and albumin to calculate the UAR. The observed in-hospital mortality was 14.5%. Non-survivors had higher pre- and post-operative median of UAR than survivors (88.39 vs. 30.99, p < 0.0001 and 106.18 vs. 26.58, p < 0.0001, respectively). Lethal outcome was predicted successfully both by UAR before surgery (area under receiver operating characteristics [AUROC] curves = 0.889; p < 0.0001) at a threshold of 61.42 and on third post-operative day (AUROC = 0.943; p < 0.0001) at a threshold = 55.89. Peri-operative UAR showed an excellent ability for prognostication of fatal outcome in patients with cIAIs.