Generalizability of the nonalcoholic steatohepatitis Clinical Research Network histologic scoring system for nonalcoholic fatty liver disease.
OBJECTIVE
The recently developed histologic scoring system for nonalcoholic fatty liver disease (NAFLD) by the nonalcoholic steatohepatitis (NASH) Clinical Research Network (CRN) is becoming increasingly popular. However, its generalizability to a community setting has not been evaluated. We conducted a study to compare a community general pathologist to an expert hepatopathologist in assessing NAFLD using the NASH CRN scoring system.


METHODS
Forty-eight consecutive patients with suspected NAFLD underwent liver biopsy. Histologic features of interest such as steatosis, lobular inflammation, balloon degeneration, fibrosis, NAFLD Activity Score (NAS), and the presence of NASH were scored in a blinded fashion by the 2 pathologists on 2 separate occasions 3 months apart.


RESULTS
The mean (± SD) length of the liver biopsy samples was 25 ± 5 mm. Interobserver agreement (κ) between 2 pathologists was 0.62 (0.45-0.80) for steatosis, 0.44 (0.23-0.65) for lobular inflammation, 0.25 (0.11-0.38) for ballooning, 0.40 for NAS (0.28-0.52), and 0.35 (0.19-0.52) for fibrosis. The 2 pathologists diagnosed "definite NASH" in a similar proportion of patients (56% vs. 57%), but their interobserver agreement was only 0.46 (0.24-0.67) as they both diagnosed different levels of NASH (borderline vs. definite) in different subjects. Intraobserver agreement was generally comparable for steatosis, lobular inflammation, NAS, and diagnosis of NASH, but not for fibrosis.


CONCLUSIONS
Clinically important differences exist between community general pathologist and expert hepatopathologist in assessing NAFLD using the NASH CRN scoring system. More studies are needed to investigate its suitability for community-based clinical practice.
Juluri
Ravi
R
Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202-2859, USA.
Vuppalanchi
Raj
R
Olson
John
J
Unalp
Aynur
A
Van Natta
Mark L
ML
Cummings
Oscar W
OW
Tonascia
James
J
Chalasani
Naga
N
D000328:Adult; D001706:Biopsy; D005234:Fatty Liver / Q000175:diagnosis* / Q000473:pathology; D005260:Female; D006801:Humans; D007249:Inflammation / Q000175:diagnosis / Q000473:pathology; D008099:Liver / Q000473:pathology*; D008103:Liver Cirrhosis / Q000175:diagnosis / Q000473:pathology; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012720:Severity of Illness Index