Body Mass Index and Liver Stiffness Affect Accuracy of Ultrasonography in Detecting Steatosis in Patients With Chronic Hepatitis C Virus Genotype 1 Infection

Abstract

Background & Aims: Few studies have evaluated the accuracy of ultrasonography in detecting steatosis in patients with chronic hepatitis C. We assessed its accuracy in detecting steatosis and factors that affect its diagnostic performance in consecutive patients with chronic hepatitis C virus genotype 1infection. Methods: We analyzed data from 515 patients with chronic hepatitis C, confirmed by liver biopsy, assessing anthropometric, biochemical, metabolic, virologic, and ultrasonography features. Transient elastography was performed to measure liver stiffness. Steatosis was identified with ultrasonography based on detection of a bright liver echo pattern. Results: Ultrasonography identified steatosis in 5% or more of parenchyma of the liver with 63.6% sensitivity, 90.4% specificity, an 87.5% positive predictive value (PPV), and a 70.3% negative predictive value (NPV). The higher the degree of steatosis (based on histology analysis), the higher the sensitivity values and NPVs (up to values of 75.3% and 93.8%, respectively, for steatosis in ≥30% of liver), and the lower the specificity values and PPVs (down to values of 69.8% and 31.7% for steatosis in ≥30% of liver, respectively). Body mass index of 30 kg/m2 or greater (odds ratio, 2.761; 95% confidence interval, 1.156-6.595; P= .02) and liver stiffness measurements of 8.9kPa or higher (odds ratio, 3.128; 95% confidence interval, 1.715-5.706; P< .001) were independent risk factors for false-negative results from ultrasonography when there was 5% or more steatosis, as well as when there was 10% or more, 20% or more, or 30% or more steatosis. Conclusions: Ultrasonography detects steatosis with low levels of accuracy in patients with chronic hepatitis C virus genotype 1 infection; it has low NPVs for amounts of steatosis of 5% or more and low PPVs for livers with moderate-severe amounts. Higher body mass indexes and liver stiffness measurements are associated with false-negative results in steatosis detection by ultrasonography