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

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 100 mg 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. [ABSTRACT FROM AUTHOR]