Objective: Still the associations between non-alcoholic fatty liver disease (NAFLD) and diabetic kidney disease assessed by either albuminuria or proteinuria have been inconsistent. The aim of study is to investigate the association between hepatic steatosis or fibrosis and albuminuria or proteinuria in Korean patients with type 2 diabetes mellitus (T2D).
Methods: This study enrolled 1,108 T2D patients. We defined non-proteinuria (NP) as having both uPCR < 150 mg/g and uACR < 30 mg/g, isolated non-albumin proteinuria (iNAP) as having both uPCR ≥ 150 mg/g and uACR < 30 mg/g, and albuminuria as having uACR ≥ 30mg/g. Hepatic steatosis and fibrotic burden were assessed using NAFLD liver fat score (NLFS), Fibrosis-4 calculator (FIB-4) index, and NAFLD fibrosis score (NFS).
Results: The prevalence of significant steatosis, defined NLFS > -0.64, was similar between groups (NP; 528/708 [74.6%] vs. iNAP; 64/91 [70.3%] vs. albuminuria; 247/309 [79.9%], p = 0.085). However, those with significant fibrosis with NFS > 0.676 were significantly higher in groups with iNAP 17/91 (18.7%) and albuminuria 51/309 (16.5%) than NP (67/708 (9.5%), p = 0.001). Both uPCR and uACR showed the correlation with NFS (uPCR; r = 0.123; p < 0.001, uACR; r = 0.064; p = 0.033). However, in multivariate logistic regression analysis, uPCR ≥ 150 mg/g was found to have stronger association with hepatic fibrosis than uACR ≥ 30 mg/g (aOR 1.55 [95% CI, 1.03-2.33] vs. aOR 1.16 [95% CI, 0.72-1.87]).
Conclusion: Subjects with iNAP and albuminuria had higher proportion of hepatic fibrosis compared to patients without proteinuria. Total proteinuria was associated with advanced liver fibrosis, while albuminuria was related to hepatic steatosis.