Accuracy of Ultrasound and Noninvasive Markers of Fibrosis to Identify Patients with Cirrhosis

Background: Accurate identification of patients with cirrhosis using noninvasive markers of fibrosis is useful for esophageal varices and hepatocellular carcinoma surveillance programs. The aims of our study were to characterize the accuracy of ultrasonography, AST-to-platelet ratio index (APRI), and FIB-4 as noninvasive markers to identify the presence of cirrhosis. Methods: We conducted a retrospective cohort study of patients who underwent liver biopsy at a large urban safety-net institution between November 2008 and July 2011. The sensitivity, specificity, positive predictive value (PPV), negative predictive value, and overall accuracy using receiver operator characteristic curve analysis for the detection of cirrhosis were calculated for each noninvasive marker. Results: Liver biopsy was performed in 388 patients, of whom 93 (24.0 %) had cirrhosis. C-statistics for APRI and FIB-4 predicting the presence of cirrhosis were 0.68 (95 % CI 0.63–0.74) and 0.73 (95 % CI 0.68–0.78), respectively. The c-statistic for a nodular appearance on ultrasound was 0.78 (95 % CI 0.72–0.83). The PPV of a shrunken nodular-appearing liver was 64.8 %; however, PPV was significantly higher in the subset with a cirrhotic-appearing liver and signs of portal hypertension (PPV 83.6 %, p = 0.01) as well as in the subset with a noninvasive fibrosis marker also suggesting cirrhosis (PPV 77.8 %, p < 0.001). Conclusion: Serum and imaging noninvasive markers of fibrosis may have insufficient accuracy when used in isolation; however, a combination of markers may allow sufficient accuracy to systematically identify patients with cirrhosis.