13C-methacetin-breath test compared to also noninvasive biochemical blood tests in predicting hepatic fibrosis and cirrhosis in chronic hepatitis C.

BACKGROUND: The (13)C-methacetin-breath test and also several noninvasive blood tests comprising routine laboratory parameters have been proposed to predict fibrosis and cirrhosis in chronic hepatitis C. The aim of the study was to compare the diagnostic accuracy between these tests referring to hepatic histology as gold standard.

METHODS: 96 patients with chronic hepatitis C virus infection underwent percutaneous liver biopsy and the (13)C-methacetin-breath test. The Fibroindex, the aspartate aminotransferase to platelet ratio index , and the aspartate aminotransferase to alanine aminotransferase ratio were used as parameters for the staging of fibrosis. The main endpoint was the area under the characteristic curves for the diagnosis of advanced fibrosis (F3-F4) and cirrhosis (F4) according to the Batts Ludwig criteria.

RESULTS: ROC analysis revealed a cut-off <14.6 per thousand best with 92.6% sensitivity and 84.1% specificity for the (13)C-methacetin-breath test, for the Fibroindex >1.82 70.4% sensitivity and 91.3% specificity, for the aspartate aminotransferase to platelet ratio >1.0 a 66.7% sensitivity and 75.4% specificity, and for the aspartate aminotransferase to alanine aminotransferase ratio >1.0 63.0% sensitivity and 59.4% specificity in predicting liver cirrhosis. The areas under the curve for the breath test, the Fibroindex, aspartate aminotransferase to platelet ratio and the aspartate aminotransferase to alanine aminotransferase ratio were 0.958, 0.845, 0.799, and 0.688, respectively, when predicting cirrhosis. For identifying patients with advanced fibrosis, the areas under the curve were 0.827, 0.804, 0.779, and 0.561, respectively. Discordances between Fibroindex (21%), aspartate aminotransferase to platelet ratio (29%) or aspartate aminotransferase to alanine aminotransferase ratio (37.6%) and liver biopsy were significantly more frequent than between (13)C-breath test (11.6%) and liver biopsy (P<0.05).

CONCLUSION: The (13)C-methacetin-breath test is more reliable in predicting advanced fibrosis and cirrhosis than simple biochemical parameters (aspartate aminotransferase to platelet ratio; aspartate aminotransferase to alanine aminotransferase ratio).