Blood urea nitrogen is elevated in patients with non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is strongly associated with many predictors of cardiovascular disease such as hypercholesterolemia, hypertriglyceridemia, insulin resistance, central obesity and the metabolic syndrome. Activation of renin-angiotensin-aldosterone system (RAAS) has been proved in patients with NAFLD. Blood urea nitrogen (BUN) elevation is a high risk factor and biomarker of RAAS activation of heart failure and coronary heart disease. The aim of the current study was to investigate BUN in patients with NAFLD.

BUN and creatinine (Cr) values of 85 patients with NAFLD and of 30 age- and gender-matched healthy individuals were compared prospectively. Liver/spleen ratios of computed tomography (CT) values were used to determine fatty liver and to evaluate fatty deposition. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were employed to estimate inflammation. We analyzed the correlation between BUN and fatty deposition or inflammation.

NAFLD patients had significantly higher BUN compared to the control cases (5.0353±1.1271 vs. 4.1263±1.0095 mmol/L; t=3.898, p<0.001). However, there was no difference in Cr (84.0941±14.4062 vs. 79.4667±16.7120 μmol/L; t=1.45, p=0.15). BUN was negatively correlated with liver/spleen ratio of CT values (r=0.009, p=0.1974), ALT (r=-0.012, p=0.941) and AST (r=-0.009, p=0.592).

We have shown for the first time in the literature, that patients with NAFLD have higher BUN. It may have prognostic value in NAFLD patients indicating a possible cardiovascular disease (CVD) risk increase.