Noninvasive fibrosis markers and chronic kidney disease among adults with nonalcoholic fatty liver in USA

Background/Aims Studies have shown that nonalcoholic fatty liver disease (NAFLD) is associated with an increased risk of chronic kidney disease (CKD). However, it is unknown whether severe liver fibrosis is associated with a higher prevalence of CKD among NAFLD. We examined the diagnostic performance of noninvasive fibrosis markers in identifying prevalent CKD among NAFLD. Methods This study represents an analysis of the National Health and Nutrition Examination Survey conducted in the USA between 1988 and 1994. NAFLD was defined by ultrasonographic evidence of hepatic steatosis without other liver diseases. CKD was defined by estimated glomerular filtration rate less than 60 ml/min/1.73 m 2 . The presence and severity of hepatic fibrosis were determined by the NAFLD fibrosis score (NFS), FIB-4 score, APRI score, and BARD score. Multiple logistic regression was performed to generate odds ratios (ORs) and receiver operating characteristic curves were used to assess the predictive values of each marker. Results A total of 4142 individuals with NAFLD were included; 200 (4.8%) had CKD. The area under the receiver operating characteristic curves was 0.77, 0.75, 0.62, and 0.51 for the multivariable equation with FIB-4, NFS, BARD, and APRI score, respectively. Compared with patients with a low probability of developing advanced liver fibrosis, individuals with a high probability of developing fibrosis showed significantly increased odds of CKD as estimated by NFS (adjusted OR: 4.92, 95% confidence interval: 2.96–8.15) and FIB-4 (adjusted OR: 2.27, 95% confidence interval: 1.05–4.52). Conclusion Advanced liver fibrosis, defined by NFS and FIB-4 scores, is associated independently with CKD among individuals with NAFLD. FIB-4 is the best predictor of an increased risk of prevalent CKD.