Non-alcoholic fatty liver disease, cytokeratin-18, and risk of type 2 diabetes mellitus: A cohort study
Abstract Background & Aims: Although many studies have shown that non-alcoholic fatty liver disease (NAFLD) is associated with type 2 diabetes mellitus (T2DM), no cohort study has explored the relationship between the histopathological grade of NAFLD and the risk of T2DM in NAFLD patients. We aimed to explore whether a higher concentration of cytokeratin-18 (CK-18), as a reliable marker of hepatic fibrosis, was associated with a greater risk of T2DM in patients with NAFLD. Methods: The population-based cohort study was based on China National Diabetes and Metabolic Disorders Survey with a follow-up of five years. NAFLD was determined by ultrasonography. T2DM were diagnosed based on oral glucose tolerance test. Serum CK-8 was measured using the M30 Apoptosense ELISA kit. Results: 457 subjects were enrolled and three groups were analyzed: a non-NAFLD group (n=363), a low-CK-18 NAFLD group (n=46), and a high-CK-18 NAFLD group (n=48). 20 (3.9%) developed diabetes during follow-up. The incidence of T2DM was 2.5%, 8.7%, and 12.5% in the non-NAFLD, low-CK-18 NAFLD, and high-CK-18 NAFLD groups, respectively. Cox proportional hazard regression showed that, compared with the non-NAFLD group, the adjusted relative risks of T2DM were 3.37 (95% CI: 1.05-10.86, P =0.042) and 4.71 (95% CI: 1.71-12.99, P =0.003), respectively, in the low-CK-18 NAFLD and high-CK-18 NAFLD groups. Conclusions: Higher CK-18 level in ultrasound-diagnosed NAFLD patients is associated with higher risk of T2DM. We recommend screening for NAFLD using ultrasound in the first instance, with, if possible, CK-18 assay being subsequently used to screen individuals at higher risk of diabetes.