The Diagnostic Accuracy of Transient Elastography for the Diagnosis of Liver Fibrosis in Bariatric Surgery Candidates with Suspected NAFLD

Severe obesity and metabolic syndrome have been implicated in the development of nonalcoholic fatty liver disease (NAFLD). We evaluated the diagnostic value of liver stiffness measurement (LSM), by transient elastography (FibroScanA (R)) in bariatric surgery candidates with suspected NAFLD. A total of 100 prospectively included consecutive severely obese subjects underwent bariatric surgery with liver needle biopsy. LSM was performed in the 15 days preceding liver biopsy. According to Kleiner's classification, 28 patients had no fibrosis, 50 had stage F1 fibrosis, 13 had stage F2 fibrosis, and nine had stage F3 fibrosis. LSMs were higher in patients with fibrosis stage F a parts per thousand yen2, than in patients with a fibrosis stage below F2 (p < 0.001). Fibrosis stage (p < 0.002), amount of steatosis (%) (p < 0.001), BMI (p < 0.02), and activity score (p = 0.027) were independently correlated with LSM. Homeostasis model assessment (HOMA) index was also significantly and independently correlated with LSM (p < 0.01). The area under the receiver operating characteristic curve (AUROC) generated by FibroScanA (R) was 0.81 A +/- 0.05 for predicting fibrosis stage F a parts per thousand yen2 and 0.85 A +/- 0.04 for predicting F3 fibrosis. The decrease in LSM 1 year after bariatric surgery was significantly correlated with changes in HOMA index (r = 0.43, p = 0.01), but not with changes in BMI or weight. FibroScanA (R) allows the early diagnosis of fibrosis in severely obese patients. Our results also suggest that FibroScanA (R) could identify a subgroup of NAFLD patients at high risk of progressive liver disease and that LSM could be used as a surrogate marker of insulin resistance. Further studies are required to evaluate the prognostic value of FibroScanA (R).