Clinical usage of serum ferritin to assess liver fibrosis in patients with non‐alcoholic fatty liver disease: Proceed with caution

Serum ferritin was recently reported to have low diagnostic accuracy for the detection of advanced fibrosis in patients with non‐alcoholic fatty liver disease (NAFLD). To corroborate these findings, we investigated the diagnostic accuracy of serum ferritin levels for detecting liver fibrosis in NAFLD patients utilizing a large Japanese cohort database. A total 1201 biopsy‐proven NAFLD patients, seen between 2001 and 2013, were enrolled into the Japan Study Group of NAFLD. Analysis was performed on data from this cohort comparing between serum ferritin levels and hepatic histology. Serum ferritin increased with increasing histological grade of steatosis, lobular inflammation and ballooning. Multivariate analyses revealed that sex differences, steatotic grade and fibrotic stage were independently associated with serum ferritin levels (P < 0.0001, <0.0001, 0.0248, respectively). However, statistical analyses performed using serum ferritin levels demonstrated that the area under the receiver–operator curve for detecting fibrosis was not adequate for rigorous prediction. Several factors including sex differences, steatosis and fibrosis were found to correlate with serum ferritin levels. Therefore, serum ferritin may have low diagnostic accuracy for specifically detecting liver fibrosis in NAFLD patients due to the involvement of multiple hepatocellular processes.