Non-invasive estimation of liver fibrosis in non-alcoholic fatty liver disease using the 13C-caffeine breath test

Abstract

Background and Aim: Fibrotic progression in non-alcoholic fatty liver disease (NAFLD) is associated with impaired hepatic function. The 13C-caffeine breath test (CBT) is a non-invasive, quantitative test of liver function. We sought to determine the utility of the CBT in detecting hepatic fibrosis in NAFLD. Methods: The CBT was applied to 48 patients with NAFLD. CBT results were compared to clinical, biochemical and histological data. Twenty-four healthy subjects served as controls. Results: Patients with simple steatosis had similar CBT values (2.28±0.71 Δ‰ per 100mg caffeine) to controls (2.31±0.85, P=1.0). However, CBT was significantly reduced in patients with non-alcoholic steatohepatitis (1.59±0.65, P=0.005) and cirrhosis (1.00±0.73, P<0.001). CBT significantly correlated with Brunt's fibrosis score (r=-0.49, P<0.001) but not with steatosis (P=0.23) or inflammation (P=0.08). CBT also correlated with international normalized ratio (r=-0.61, P<0.001), albumin (r=0.37, P=0.009), aspartate aminotransferase/alanine aminotransferase (r=-0.34, P=0.018) and platelets (r=0.31, P=0.03). On multivariate analysis, age (odds ratio 1.12, 95% confidence interval 1.042-1.203, P=0.002) and CBT (OR 0.264, 95% CI 0.084-0.822, P=0.02) were independent predictors of significant fibrosis (F≥2). CBT yielded an area under the receiver operating characteristic curve of 0.86 for the diagnosis of cirrhosis. Conclusions: The CBT reflects the extent of hepatic fibrosis in NAFLD and represents a non-invasive predictor of fibrosis severity in this condition. © 2011 Journal of Gastroenterology and Hepatology Foundation and Blackwell Publishing Asia Pty Ltd.