Recommendations for the management of non-alcoholic fatty liver disease (NAFLD)

Definition and epidemiology

Non-alcoholic fatty liver disease (NAFLD) is a growing clinical and epidemiological problem worldwide. The prevalence of the disease is correlated with the level of development of a given society, however increasingly across the world the problem affects various age and social groups [1, 2]. The definition of NAFLD should include both different stages of the disease and the wide spectrum of clinical manifestations involving not only the liver. Most patients with NAFLD experience nutritional and metabolic disorders, mainly obesity, diabetes and dyslipidaemia. The definition of NAFLD requires that there is evidence of hepatic steatosis by imaging and/or histopathological examination (preferred option) and there are no other causes for hepatic fat accumulation, primarily excessive alcohol consumption, long-term use of medications inducing hepatic steatosis, infection by steatogenic pathogens (e.g. geno­type 3 of the hepatitis C virus) and hereditary lipid disorders [3, 4].
Histologically, NAFLD may be further categorized into non-alcoholic fatty liver (NAFL) and non-alcoholic steatohepatitis (NASH). The distinction between stages of NAFLD is of fundamental importance for prognosis and therapy. NAFL is defined as the presence of > 5% of steatotic hepatocytes without features of hepatocyte injury and ballooning degeneration. The diagnosis of NASH requires the presence of inflammation and hepatocyte injury (most commonly ballooning degeneration), with fibrosis not being a prerequisite for diagnosing NASH [4-6].
The prevalence of NASH in the general population and across different regions/countries is difficult to estimate. Since NASH must be confirmed histopathologically, only in some patients the diagnosis can be made in a methodologically correct manner. On the other hand, the obesity “epidemic”, growing prevalence of diabetes and evidence of hepatic steatosis in imaging studies in a large number of patients, give grounds to assume that NAFLD, but also NASH, affect a significant percentage of the population [7, 8]. One of the largest meta-analyses, published by Younossi et al., shows that NASH confirmed by liver biopsy affects almost 60% of patients with liver disease (biopsy for clinical indications) and between 2 and 6% of the general population [9]. If these estimates are correct, NASH and its consequences occur much more commonly than any other liver disease.

Risk factors

Recognized factors...


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