Modification of a simple clinical scoring system as a diagnostic screening tool for non-alcoholic steatohepatitis in Japanese patients with non-alcoholic fatty liver disease

Aims/introduction: We reinvestigated the clinical usefulness of the modified NAFIC scoring system, modified by changing the weightage assigned to the fasting serum insulin level based on the importance of hyperinsulinemia in the pathogenesis of non-alcoholic steatohepatitis (NASH), in Japanese patients with non-alcoholic fatty liver disease (NAFLD) who had undergone liver biopsy.

Materials and methods: The NAFIC score is conventionally calculated as follows: serum ferritin ≥200 ng/mL (female) or ≥300 ng/mL (male), 1 point; serum fasting insulin ≥10 μU/mL, 1 point; and serum type IV collagen 7 s ≥5.0 ng/mL, 2 points. A total of 147 patients with NAFLD who had undergone liver biopsies were included in the estimation group. To validate the modified scoring system, 355 patients from nine hepatology centers in Japan were also enrolled.

Results: In the estimation group, 74 (50.3%) patients were histologically diagnosed as having NASH, whereas the remaining 73 (49.7%) were diagnosed as not having NASH. As the percentage of NASH patients increased not only among participants with serum insulin levels greater than 10 μU/mL, but also in those with serum levels greater than 15 μU/mL, we advocated use of the modified NAFIC score, as follows: serum fasting insulin 10-15 μU/mL, 1 point and ≥15 μU/mL, 2 points. The modified NAFIC score showed improved sensitivity and negative predictive value for the diagnosis of NASH. This finding was also confirmed in the validation group.

Conclusions: The modified NAFIC scoring system could be a clinically useful diagnostic screening tool for NASH.