Relationship between urinary fractional excretion of sodium and life prognosis in liver cirrhosis patients

Aim: Renal vasoconstriction in generalized vasodilatation with blood pooling and the consequent reduction in effective arterial volume is the pathophysiological basis of liver cirrhosis (LC). Low levels of fractional excretion of sodium (FENa) are an effective marker of hypoperfusion of the renal artery. However, the relationship between levels of FENa, LC severity and life prognosis has not yet been elucidated.

Methods: We examined 57 LC patients (39 men and 18 women; mean age, 70.5 ± 8.8 years; underlying liver disease, type B hepatitis in eight patients, type C hepatitis in 37, alcoholic hepatitis in four and others in eight) with renal dysfunction (estimated glomerular filtration rate (eGFR) <60 mL/min) who were admitted to our hospital.

Results: Nine patients died because of uremia, liver failure, gastrointestinal bleeding and infection. No differences were found in patient background and blood pressure. However, in addition to differences in the levels of aspartate aminotransferase (AST), cholinesterase, albumin, prothrombin time (PT), eGFR and Model for End-Stage Liver Disease (MELD) score, the patients who died had significant differences in levels of FENa. The levels of FENa were significantly and inversely correlated with blood urea nitrogen, total bilirubin, AST, Child-Pugh score and MELD score, and were significantly and positively correlated with cholinesterase, albumin and PT. Moreover, the sensitivity (88%) and specificity (93%) of the levels of FENa of less than 0.4% to predict death were remarkably high.

Conclusion: Levels of FENa may reflect LC severity and may be associated with the life prognosis of LC patients.