Fatty liver disease affects one in four in Europe, study estimates

Keith Alcorn
Published:
07 September 2020
Image: Bru-nO/Pixabay

Non-alcoholic fatty liver disease affects one in four people in the general population in Europe and just over one in twenty people have advanced liver fibrosis, a meta-analysis of 33 studies from 15 European countries presented at the Digital International Liver Congress shows.

Non-alcoholic fatty liver disease (NAFLD) occurs when fat accumulates in the liver. People with diabetes or metabolic syndrome have a higher risk of developing non-alcoholic fatty liver disease. Fat accumulation can lead to inflammation in the liver and damage (fibrosis). Liver damage due to fat accumulation is called non-alcoholic steatohepatitis (NASH).

NAFLD is a growing public health problem, but the prevalence is unclear. Studies have used differing methods to diagnose NAFLD, employing either blood tests or imaging to diagnose the condition. A meta-analysis published by the Center for Disease Analysis in 2018, including general population studies from the largest European countries and the United States, estimated prevalence of between 25 and 30% in western  Europe.

To assess the prevalence of NAFLD and NASH in Europe, researchers from six European countries carried out a systematic review and meta-analysis of studies published up to 2019. Studies were eligible for inclusion if they reported prevalence in the general population but were excluded if they investigated prevalence only in people with metabolic conditions or in children. Studies were also excluded if they did not report data on alcohol consumption or if they failed to exclude other causes of liver disease when calculating prevalence.

The research team identified 19 studies including 42,580 people that diagnosed NAFLD by non-invasive imaging and nine studies including 84,235 people that assessed NAFLD prevalence by blood tests using the Fatty Liver Index. Twelve studies reported on the prevalence of NASH (4696 participants) and five on the prevalence of advanced fibrosis (7270 participants).

The cohorts were diverse, with wide variations in the prevalence of obesity, type 2 diabetes and metabolic syndrome. They also reported wide variations in the prevalence of NAFLD, ranging from 10.4% in a Swedish study of 1015 people with a median age of 57 years and a diabetes prevalence of 7%, to 48% in a study carried out in Italy (890 people) (median age 53 years and diabetes prevalence 19%).

A meta-analysis of NAFLD prevalence studies found a pooled prevalence of 27%, with no difference in the final result between studies which used imaging or blood tests to assess prevalence.

Studies assessing the prevalence of NASH were inevitably biased due to referral for biopsy on the basis of clinical indication. The 12 studies found that 64% of 4696 NAFLD patients referred for biopsy had NASH.

Meta-analysis of five studies of advanced fibrosis prevalence in the general population found a prevalence of 6%. These studies used blood tests to assess the prevalence of F3 or f4 fibrosis (advanced fibrosis or cirrhosis).

The study authors say this the largest analysis to date of the burden of NAFLD in Europe and needs to be followed up by an economic analysis of the potential benefits of non-invasive testing for advanced fibrosis in the general population, given the high prevalence detected across studies included in this meta-analysis.

Reference

Petta S et al. Europe’s largest meta-analysis on the prevalence of non-alcoholic fatty liver disease and non-alcoholic steatohepatitis and advanced fibrosis (F3-F4). Journal of Hepatology (supplement 1) [Digital International Liver Congress], THU053, S166, 2020.