Nonalcoholic fatty liver disease (NAFLD) is a multisystemic clinical condition that presents with a wide spectrum of extrahepatic manifestations, such as obesity, type 2 diabetes mellitus, metabolic syndrome, cardiovascular diseases, chronic kidney disease, extrahepatic malignancies, cognitive disorders, and polycystic ovarian syndrome. Among NAFLD patients, the most common mortality etiology is cardiovascular disorders, followed by extrahepatic malignancies, diabetes mellitus, and liver-related complications. Furthermore, the severity of extrahepatic diseases is parallel to the severity of NAFLD. In clinical practice, aware-ness of the associations of concomitant diseases is of major importance for initiating prompt and timely screening and multidisciplinary management of the disease spectrum. In 2020, a consensus from 22 countries redefined the disease as metabolic (dysfunction)-associated fatty liver disease (MAFLD), which resulted in the redefinition of the corresponding population. Although the patients diagnosed with MAFLD and NAFLD mostly overlap, the MAFLD and NAFLD populations are not identical. In this review, we compared the associations of key extrahepatic diseases between NAFLD and MAFLD.

Nonalcoholic fatty liver disease (NAFLD) is a multisystemic clinical condition that presents with a wide spectrum of extrahepatic manifestations, such as obesity, type 2 diabetes mellitus, metabolic syndrome, cardiovascular diseases, chronic kidney disease, extrahepatic malignancies, cognitive disorders, and polycystic ovarian syndrome. Among NAFLD patients, the most common mortality etiology is cardiovascular disorders, followed by extrahepatic malignancies, diabetes mellitus, and liver-related complications. Furthermore, the severity of extrahepatic diseases is parallel to the severity of NAFLD. In clinical practice, aware-ness of the associations of concomitant diseases is of major importance for initiating prompt and timely screening and multidisciplinary management of the disease spectrum. In 2020, a consensus from 22 countries redefined the disease as metabolic (dysfunction)-associated fatty liver disease (MAFLD), which resulted in the redefinition of the corresponding population. Although the patients diagnosed with MAFLD and NAFLD mostly overlap, the MAFLD and NAFLD populations are not identical. In this review, we compared the associations of key extrahepatic diseases between NAFLD and MAFLD.

Background/Aims: Advanced fibrosis (F≥3) indicates poor outcomes in nonalcoholic fatty liver disease (NAFLD). Here, we examined the diagnostic performance of the fibrosis-4 index (FIB-4) and NAFLD fibrosis score (NFS) for detecting (or excluding) advanced fibrosis in patients with biopsy-proven NAFLD. Methods: The diagnostic performance of each noninvasive test according to previously identified cutoff points indicating low and high risk for advanced fibrosis was determined in 463 patients with NAFLD. Patients who scored <1.3 and >2.67 on the FIB-4 were considered at low and high risk for advanced fibrosis, respectively. Patients who scored <–1.455 and >0.676 on the NFS were considered at low and high risk for advanced fibrosis, respectively. Results: Eighty-one patients (17.5%) had biopsy-proven advanced fibrosis (F≥3). The published FIB-4 cutoff values for low and high risk were able to exclude advanced fibrosis with negative predictive values (NPVs) of 0.907 and 0.843 and specificities of 74% and 97%, respectively. The published NFS cutoff values for low and high risk were able to exclude advanced fibrosis with NPVs of 0.913 and 0.842 and specificities of 63% and 96%, respectively. If biopsies were performed in only patients with a FIB-4 above the low cutoff point (≥1.3), 67.1% could be avoided. Conversely, if biopsies were performed in only patients with an NFS above the low cutoff point (≥–1.455), 57.0% could be avoided. Conclusions The main clinical utility of the FIB-4 and NFS in patients with NAFLD lies in the ability to exclude, not identify, advanced fibrosis.