Evaluation of non-invasive diagnostic methods as indicators of fibrosis in patients with nonalcoholic fatty liver disease

Aims: Non-alcoholic fatty liver disease (NAFLD) is an increasingly recognized cause of chronic-liverdisease which may be diagnosed incidentally in asymptomatic patients. Non-alcoholic steatohepatitis (NASH) may cause cirrhosis and hepatocellular carcinoma. To date, no established non-invasive test exists to accurately predict fibrosis in NASH. Although liver biopsy is the gold standard for the diagnosis of NASH, it occasionally has some serious complications. We aimed to compare the diagnostic accuracy of some widely used non-invasive fibrosis scoring systems. Methods: We retrospectively assessed the files of 40 subjects with biopsy proven diagnosis of NAFLD. The subjects were grouped as mild and advanced fibrosis. Demographic, medical historical, and laboratory data were recorded. FIB4 index, APRI-, BARD-, and BAAT-scores were calculated. The agreement between biopsy findings and non-invasive scoring systems was assessed with Kappa statistics. Results: 17 of the patients (58% males, mean age 58.8 years) had advanced fibrosis while 23 of them had mild fibrosis (52% males, mean age 54.5 years). Patients with advanced fibrosis had significantly higher AST and fasting glucose levels and waist circumferences (p<0.05 for each). None of the studies noninvasive scoring systems had a strong or independent correlation with biopsy findings. BAAT and BARD scores were relatively sensitive (88.9% for each) but non-specific (12.9 and 35.5, respectively), APRI score was highly specific (95.7%) but non-sensitive (35%), and FIB4 score was moderately sensitive (65%) and specific (69.6%) to detect advanced fibrosis. Conclusions: In this study, none of the non-invasive tests used were independent factors for advanced fibrosis. These scores were more likely to exclude rather than detect advanced fibrosis. When the increase in NAFLD prevalence is considered, it is obvious that studies performed with more reliable noninvasive tests which would be used to detect or exclude advanced fibrosis are needed.