Abstract
BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is associated with chronic kidney disease (CKD). However, the causal relationship between NAFLD and CKD is uncertain, particularly in patients with type 2 diabetes mellitus (T2DM). We aimed to investigate the association between the presence and severity of NAFLD and incident CKD in patients with T2DM. METHODS: In this longitudinal cohort study of patients with T2DM, 3,188 patients with preserved renal function were followed up for the occurrence of incident CKD. NAFLD was defined as the presence of hepatic steatosis on ultrasonography, without any other causes of chronic liver disease. Advanced liver fibrosis of NAFLD was defined as a fibrosis-4 index ≥2.67. CKD was defined as an estimated glomerular filtration rate <60 mL/min/1.73 m2. RESULTS: At baseline, 1,729 (54.2%) patients had NAFLD, of whom 94 (5.4%) had advanced liver fibrosis. During the follow-up of 8.3±3.6 years, 472 (14.8%) patients developed incident CKD: 220 (15.1%) in the non-NAFLD group, 231 (14.1%) in the NAFLD without advanced fibrosis group and 28 (31.1%) in the NAFLD with advanced fibrosis group. There was no increased risk of incident CKD in the NAFLD group compared to the non-NAFLD group (P=0.435). However, among patients with NAFLD, advanced liver fibrosis was associated with an increased risk of CKD (adjusted hazard ratio, 1.75; 95% confidence interval, 1.15 to 2.66; P=0.009). CONCLUSION: Advanced liver fibrosis in patients with NAFLD is independently associated with an increased risk of incident CKD in patients with T2DM.