Accuracy of Noninvasive Testing for Advanced Fibrosis in Patients With HCV

The evaluation of noninvasive tests to identify advanced hepatic fibrosis in patients with chronic hepatitis C virus infections (HCV) and end-stage renal disease (ESRD) showed a modest increase in accuracy for patients with increased alanine aminotransferase (ALT) levels. The results were inaccurate, however, for patients with normal ALT levels. These results were published in Clinical Gastroenterology & Hepatology.

This retrospective study collected data from 139 patients with HCV and ESRD regarding the ratio of aspartate amino transferase to alanine aminotransferase (AST:ALT), AST platelet ratio index (APRI), FIB-4 score, fibrosis index score, and King’s score. These results were then compared with findings from the reference standard of histologic analyses of biopsies.

Using the established cutoffs for advanced hepatic fibrosis derived from patients with HCV, 3 tests demonstrated reasonable accuracy: APRI, King’s Score and FIB-4. All 3 tests demonstrated similar diagnostic accuracy: 73.4%, 70.4% and 77.0%, respectively. The investigators attempted to increase the accuracy of the tests by using data from patients with HCV and ESRD to optimize the cutoff points. The same 3 tests demonstrated significant accuracy in diagnosing advanced hepatic fibrosis. The FIB-4 scores demonstrated accuracy with an area under the receiver operating characteristic (AUROC) of 0.71 (95% CI, 0.61–0.80), the King’s score with an AUROC of 0.69 (95% CI, 0.58–0.80), and the APRI with an AUROC of 0.68 (95% CI, 0.59–0.79).

Previous research has suggested that patients with ESRD show normalized ALT levels, therefore researchers also used this level as a stratification in determining the accuracy of the noninvasive tests. Results showed that among patients with elevated ALT, the APRI, King’s Score and FIB-4 again had the highest accuracy in detecting advanced fibrosis, as well as solid negative predictive values. However, when applied to patients with normal ALT levels, all 5 tests were inaccurate with AUCs of 0.48, 0.47, 0.50, 0.53, 0.46 for AST:ALT ratio, APRI, King’s Score, FIB-4, and Fibrosis Index, respectively; diagnostic accuracy ranged from 25% for AST;ALT ratio to 73.6% for Fibrosis Index.

This report did have several limitations, including that it was completed at a single center with a majority African American study population and a predominance of men, thus limiting its generalizability. The study also had limited statistical power owing to only 34 of 139 patients having advanced fibrosis. Further, there was a gap between liver biopsy and the acquisition of laboratory data to calculate the models, which was chosen to reduce changes in clinical status that may influence noninvasive fibrosis assessment. However, limited data exists regarding the stability of aminotransferase levels over time in patients with HCV.

Given the high numbers of patients with normal ALT levels and the failure of all tests to detect advanced fibrosis in these patients, no test can be recommended for this group. Investigators concluded that further data on noninvasive tests are needed.

Reference

Schmoyer CJ, Kumar D, Gupta G, Sterling RK. Diagnostic accuracy of non-invasive tests to detect advanced hepatic fibrosis in patients with hepatitis C and end-stage renal disease [published online February 18 2020]. Clin Gastroenterol Hepatol. doi:10.1016/j.cgh.2020.02.019