Serum urea:albumin ratio as a prognostic marker in critical patients with non-chronic kidney disease.

Routine laboratory investigations play an important role in estimating the risk of mortality in intensive care unit (ICU) patients. The significance of urea:albumin ratio (UAR) in predicting the stay and mortality of ICU patients is not known. It is a retrospective study of patients admitted to ICU (n = 412) with non-chronic kidney disease (non-CKD). Receiver-operating characteristics (ROC) analysis for predicting mortality was carried out to find area under curve (AUC) and threshold levels. Analysis of survival probability was carried out by Kaplan-Meier method and Log-rank test. The AUC to predict mortality were 0.695, 0.767 and 0.791 for serum albumin, urea and UAR, respectively. The threshold levels for albumin, urea and UAR were 2.8 g/dL, 53 mg/dL, and 23.44 mg/g, respectively. The highest odds ratio (OR) of 9.75 to predict mortality at threshold level was observed for UAR, while OR were 7.0 and 3.62 for serum urea and albumin, respectively. The serum urea above and albumin below threshold level were associated with increase in ICU stay of >3 days but the highest OR of 4.73 to predict stay of >3 days was observed for UAR. Kaplan-Meier survival analysis shows significant (p < 0.001) difference at the threshold value of UAR. Serum urea and albumin are found to be an independent predictor for the mortality and stay; however an increased UAR value is the best parameter in predicting mortality and stay in ICU patients with non-CKD illness.