Background and Aims: Fatty infiltration of liver may induce insulin resistance (IR), and a proportion of patients with nonalcoholic fatty liver disease (NAFLD) is diagnosed with nonalcoholic steatohepatitis. Transient elastography is gaining popularity as a means of non-invasively determining both liver stiffness (fibrosis level) and degree of fatty infiltration, expressed as controlled attenuation parameter (CAP) value. Methods: The aims of this study were to investigate the association between IR and level of fatty liver, and to identify the group at a greater risk of nonalcoholic steatohepatitis using transient elastography and other noninvasive fibrosis markers. A total of 169 patients without chronic hepatitis B and C were analyzed. Results: The CAP value was significantly associated with IR (HOMA-IR ≥2.5; AUROC = 0.81), and the optimal cut-off to discriminate IR was 264 dB/m. The liver stiffness measurement and aspartate aminotransferase-to-platelet ratio index values were significantly higher for CAP ≥264 than in CAP <264. The 9 patients among the overall 169 patients (5.3%) and among the 102 NAFLD patients (8.8%) who showed ≥264 dB and ≥7.0 kPa in transient elastography could represent good candidates for liver biopsy. Conclusions: Evaluation of NAFLD based on CAP values was useful in diagnosing IR. About 9% of NAFLD patients in a Japanese outpatient clinic with a few metabolic complications might be considered good candidates for liver biopsy to confirm nonalcoholic steatohepatitis.
Keywords: CAP; Fibrosis marker; Insulin resistance; NAFLD; NASH; Transient elastography.