Serum Urea at Admission Is a Predictor of Mortality in Patients With Acute on Chronic Liver Failure

Abstract

Introduction: Occurrence of acute kidney injury [AKI] in Acute on chronic liver failure (ACLF) negatively impacts their survival. Only elevated serum creatinine is used to assess AKI and predict survival in ACLF. There is little data on impact of serum urea on outcome; serum urea values are ignored for prognostication. We performed a prospective study to evaluate the impact of serum urea on survival in ACLF. Methods: This study was conducted in ACLF patients hospitalised in Gastroenterology Department of SCB Medical College in India from October 2016 to March 2018. Demographic, clinical, laboratory parameters were recorded and outcome compared in patients with special reference to admission serum urea level. Results: Consecutive decompensated cirrhosis (DC) patients (n=439) were screened for ACLF as per The Asian Pacific Association for the Study of the Liver (APASL) criteria. 113 (25.7%) of them had ACLF. Out of the 113 ACLF cases, 78 (69%) had AKI as per AKIN (Acute Kidney Injury Network) criteria. Alcohol was the commonest underlying cause of CLD (74.3%) and continued alcohol intake (61%) was the commonest precipitant of ACLF. On multivariate analysis, admission serum urea (not serum creatinine) was found to be an independent predictor of mortality in ACLF both at 28 days; p=.001, AHR 1.014(1.006-1.023) and 90 days; p<.001, AHR 1.016(1.008-1.024) and also in ACLF patients with AKI, both at 28 days; p=0.002, AHR 1.014 (1.005-1.023) and 90 days; p=.001, AHR 1.016 (1.007-1.025). The discrimination ability between survivors and deceased is higher with serum urea [AUROC 28 days; 0.772 (0.686-0.859), 90 days; 0.780(0.695-0.866); 95% CI] than with serum creatinine [AUROC 28 days; 0.760(0.669-0.850), 90 days; 0.768(0.680-0.856); 95% CI]. Conclusion: In our institution, about one fourth of decompensated cirrhotic patients had ACLF, and more than two thirds of them were associated with AKI. Admission serum urea was found to be a better predictor of mortality than serum creatinine. Hence serum creatinine can be replaced by serum urea as a better predictor of mortality [both 28 and 90 days' mortality] in ACLF patients.