Performance and limitations of steatosis biomarkers in patients with nonalcoholic fatty liver disease

BACKGROUND

Several steatosis biomarkers are available with limited independent validation.

AIM

To determine diagnostic value and limitations of several steatosis biomarkers using liver biopsy as reference standard in a large cohort of patients with suspected NAFLD.

METHODS

Three hundred and twenty-four consecutive liver biopsies were included. Histological steatosis was categorised as none (<5%), mild (5-33%), moderate (33-66%) and severe (>66%). Five steatosis biomarkers were measured: fatty liver index (FLI), NAFLD liver fat score (NAFLD-LFS), hepatic steatosis index (HSI), visceral adiposity index (VAI) and triglyceride × glucose (TyG) index.

RESULTS

Steatosis grades prevalence was: none 5%, mild 39%, moderate 30% and severe 27%. Except for VAI, the steatosis biomarkers showed a linear trend across the steatosis grades. However, their correlation with the histological amount of steatosis was only weak-moderate. All steatosis biomarkers had an adequate diagnostic accuracy for the presence of steatosis: AUROCs for FLI, LFS, HSI, VAI and TyG were 0.83, 0.80, 0.81, 0.92 and 0.90. However, their ability to quantify steatosis was poor: none of them distinguished between moderate and severe steatosis and the AUROCs for predicting steatosis >33% were 0.65, 0.72, 0.65, 0.59 and 0.59 for FLI, LFS, HSI, VAI and TyG. Both fibrosis and inflammation significantly confounded the association between steatosis biomarkers and steatosis. The steatosis biomarkers were all correlated with HOMA-IR, independent from histological steatosis.

CONCLUSIONS

All five steatosis biomarkers can diagnose steatosis and are correlated with insulin resistance. They are confounded by fibrosis and inflammation, and do not accurately quantify steatosis; this may limit their clinical utility. More research is needed to identify truly independent and quantitative markers of steatosis.

A systematic review of follow-up biopsies reveals disease progression in patients with non-alcoholic fatty liver

BACKGROUND & AIMS

Disease progression in non-alcoholic fatty liver disease (NAFLD) is not well understood and there is controversy about whether non-alcoholic fatty liver (NAFL, i.e., steatosis alone or with mild inflammation not qualifying for steatohepatitis) can evolve towards steatohepatitis (NASH) with fibrosis.

METHODS

We reviewed 70 patients with untreated NAFLD and with two biopsies performed more than one year apart. Clinical and biological data were recorded at the time of both biopsies. Alcohol consumption did not change during follow-up.

RESULTS

Initially 25 patients had NAFL and 45 had NASH and/or advanced fibrosis. After a mean follow-up of 3.7 years (s.d. 2.1), 16 NAFL patients developed NASH, eight with severe ballooning and six with bridging fibrosis on the follow-up biopsy. Patients with mild lobular inflammation or any degree of fibrosis were at higher risk of progression than those with steatosis alone. Those with unambiguous disease progression were older and had worsening of their metabolic risk factors (higher weight and more diabetes at baseline and during follow-up). In the whole cohort, ballooning progression and bridging fibrosis often occurred together and co-existed with a reduction in ALT, higher weight gain, and a higher incidence of diabetes during follow-up.

CONCLUSIONS

A substantial proportion of patients with NAFL can progress towards well-defined NASH with bridging fibrosis, especially if metabolic risk factors deteriorate. Even mild inflammation or fibrosis could substantially increase the risk of progression when compared to steatosis alone. Current monitoring practices of these patients should be revised.

A systematic review of follow-up biopsies reveals disease progression in patients with non-alcoholic fatty liver

BACKGROUND & AIMS

Disease progression in non-alcoholic fatty liver disease (NAFLD) is not well understood and there is controversy about whether non-alcoholic fatty liver (NAFL, i.e., steatosis alone or with mild inflammation not qualifying for steatohepatitis) can evolve towards steatohepatitis (NASH) with fibrosis.

METHODS

We reviewed 70 patients with untreated NAFLD and with two biopsies performed more than one year apart. Clinical and biological data were recorded at the time of both biopsies. Alcohol consumption did not change during follow-up.

RESULTS

Initially 25 patients had NAFL and 45 had NASH and/or advanced fibrosis. After a mean follow-up of 3.7 years (s.d. 2.1), 16 NAFL patients developed NASH, eight with severe ballooning and six with bridging fibrosis on the follow-up biopsy. Patients with mild lobular inflammation or any degree of fibrosis were at higher risk of progression than those with steatosis alone. Those with unambiguous disease progression were older and had worsening of their metabolic risk factors (higher weight and more diabetes at baseline and during follow-up). In the whole cohort, ballooning progression and bridging fibrosis often occurred together and co-existed with a reduction in ALT, higher weight gain, and a higher incidence of diabetes during follow-up.

CONCLUSIONS

A substantial proportion of patients with NAFL can progress towards well-defined NASH with bridging fibrosis, especially if metabolic risk factors deteriorate. Even mild inflammation or fibrosis could substantially increase the risk of progression when compared to steatosis alone. Current monitoring practices of these patients should be revised.