Targeting Insulin Resistance and Liver Fibrosis: CKD Screening Priorities in MASLD

Background and Aims: Chronic kidney disease (CKD) is a recognized extra-hepatic disease of nonalcoholic fatty liver disease (NAFLD). With the redefinition of NAFLD as metabolic dysfunction-associated steatotic liver disease (MASLD), the importance of cardiovascular metabolic factors in MASLD has been highlighted. However, whether MASLD remains independently associated with the prevalence of CKD is yet to be determined. Method: We analyzed data from 6567 non-pregnant adults from the National Health and Nutrition Examination Survey 2017-2020. MASLD was identified using liver ultrasound transient elastography and five cardiovascular risk factors. Multivariate logistic regression, subgroup analysis, and restricted cubic splines were employed to explore the associations and interactions within the data. Results: The prevalence of CKD across MASLD subgroups with different combinations of cardiometabolic risk factors varied. Univariate regression analysis indicated a significant association between MASLD and CKD (OR: 1.68, p < 0.001). This association was not significant after adjusting for diabetes (OR: 0.94, p = 0.74) or insulin resistance (OR: 1.00, p = 0.98) and was not significant in the fully adjusted model (OR: 0.87, p = 0.64). Subgroup analysis confirmed insulin resistance as a modifier in the MASLD-CKD relationship (p for interaction = 0.02). Multivariate analysis revealed that liver stiffness measurements (LSMs) were independently associated with CKD. LSM values showed an S-shaped correlation with CKD, with risk increasing above the 8.612 kPa threshold. Conclusions: This study suggests that the direct relationship between MASLD and CKD diminished when accounting for insulin resistance. Nevertheless, liver fibrosis emerges as an independent CKD risk factor, emphasizing the critical need for targeted CKD screening among MASLD patients, particularly those with insulin resistance or advanced fibrosis.