Division of Nephrology, Department of Internal Medicine, Yeungnam University Hospital, Daegu, Republic of Korea
Background: Non-alcoholic fatty liver disease (NAFLD) is associated with the dysregulation of multiple metabolic and inflammatory pathways. These can lead to extrahepatic disorders involving the kidney, a vulnerable organ responsible for extra-renal complications. Evaluating the association between NAFLD and low-grade albuminuria as a renal complication would be helpful to better understand the pathophysiology and extra-hepatic complications of NAFLD.
Patients and Methods: Our study extracted data from database obtained a representative population sample. Overall, 3867 men were included in this survey. Our study included only men without diabetes mellitus, with a urinary albumin/creatinine ratio < 30 mg/g (n = 1390). Low-grade albuminuria was defined by a urinary albumin/creatinine ratio within the highest quartile. The fatty liver index was calculated in accordance with Bedogni's equation. We defined the NAFLD group as patients with a fatty liver index of ≥ 60.
Results: In the multivariate analysis, the urinary albumin/creatinine ratio in the non-NAFLD and NAFLD groups was 3.05 ± 0.14 and 5.19 ± 0.42, respectively (P < 0.001). The correlation coefficients between the fatty liver index and urinary albumin/creatinine ratio were 0.124 in the Pearson's correlation test and 0.084 in the partial correlation test (P < 0.001 and P = 0.002, respectively). Linear regression analysis showed a positive association between the fatty liver index and the urinary albumin/creatinine ratio on multivariate analysis. Logistic regression analysis showed that the odds ratio for low-grade albuminuria with NAFLD was 2.31 (95% confidence interval, 1.47-3.61; P < 0.001) on the multivariate analysis. Subgroup analyses according to the presence of metabolic syndrome or age (< 50 or ≥ 50 years) showed that the association between NAFLD and the urinary albumin/creatinine ratio was stronger for participants without metabolic syndrome and in those aged < 50 years.
Conclusion: NAFLD was associated with low-grade albuminuria in men without diabetes mellitus in this study. Therefore, men with a relatively high fatty liver index or NAFLD should be closely monitored for low-grade albuminuria, especially in absence of metabolic syndrome.
Keywords: Non-alcoholic fatty liver disease, albuminuria, metabolic syndrome