Non-alcoholic fatty liver disease and the risk of fibrosis in Italian primary care services GPS-NAFLD Study

Background and aims The prevalence of non-alcoholic fatty liver disease (NAFLD) is increasing globally. This study aimed to determine the prevalence of NAFLD and the probability of liver fibrosis in Italian primary care services. Methods We carried out a population-based and nested case-control study including all individuals aged 18 years and above registered at Italian primary care services. Data were collected from the general practitioners' network from 2010 to 2017. NAFLD cases were identified via the ICD-9-CM and Hepatic Steatosis Index score > 36 and were matched each up to 10 controls. Other causes of liver diseases were excluded. The risk of fibrosis was assessed using the FIB-4 and NAFLD fibrosis scores (NFS). Results NAFLD was present in 9% of the primary care population with high regional variability. Among NAFLD subjects: 25% had diabetes, 10% had chronic kidney disease, 11% had cardiovascular disease and 28% were obese. Furthermore, 30% had at least two comorbidities and 13% had cirrhosis. Once cirrhosis was excluded, the risk of any degree of fibrosis was 13.8% with NFS and 20.5% with FIB-4 in subjects <65 years. Conclusions Even if there is an identification gap in primary care, recorded cases with NAFLD have a high frequency of associated comorbidities. Despite regional variability, a close relation between cirrhosis and NAFLD exists (OR: 3.48, 95% CI: 3.23-3.76). Therefore, the use of non-invasive tests should be promoted in primary care as a useful tool for the early identification of fibrosis risk, independently of evidence of steatosis.