Is cryptogenic cirrhosis different from NASH cirrhosis?

BACKGROUND & AIMS: We hypothesized that patients currently diagnosed with cryptogenic cirrhosis (CC) have truly 'cryptogenic' liver disease, which is unlikely to have evolved from NASH. The aim of this study is to characterize patients with CC, and compare their characteristics to patients with cirrhosis of other etiologies.

METHODS: To investigate this, we compared the clinical characteristics of adults with CC (n = 7,999) to those with cirrhosis caused by non-alcoholic steatohepatitis (NASH) (n = 11,302), alcohol (n = 21,714) and autoimmune hepatitis (n = 3,447), using the UNOS database from 2002-16. We performed an age, gender and year of listing matched comparison of CC and NASH (n = 7,201 in each group), and also stratified patients by the presence of obesity or diabetes mellitus (DM).

RESULTS: From 2002 to 2016, patients listed with a diagnosis of NASH increased from about 1% to 16% while CC decreased from 8% to 4%. A logistic regression model using the entire United Network for Organ Sharing data (n = 138,021) suggested that the strongest predictors of NASH were type 2 DM, obesity, age ≥60 years, female gender and white race. Type 2 DM was more common in patients with NASH (53%) than those with CC (29%), alcoholic cirrhosis (16%) and autoimmune hepatitis (16%), and obesity was more common in NASH (65.3%) compared to the other three groups (33-42%). There were more white individuals (82.3%) in the NASH group and a lower prevalence of black, Hispanic and Asian individuals, compared to the other three groups. Hepatocellular carcinoma was more commonly seen in NASH (19% vs. 9-13% in the other groups) and this is not influenced by obesity and type 2 DM. The differences between CC and NASH remained unchanged even when two groups were matched for age, gender and year of listing, or when stratified by the presence or absence of obesity or type 2DM.

CONCLUSIONS: Based on risk perspectives, CC should not be equated with the term 'NASH cirrhosis'.

LAY SUMMARY: We hypothesized that cryptogenic cirrhosis is a distinct condition from cirrhosis caused by non-alcoholic steatohepatitis (NASH). By comparing cryptogenic cirrhosis with cirrhosis of other causes, we found clear clinical differences. Therefore, cryptogenic cirrhosis should not be considered the same as NASH cirrhosis. Further investigations are required to identify unknown causes of cirrhosis.