Glucometabolic characteristics and higher vascular complication risk in Korean patients with type 2 diabetes with non-albumin proteinuria

Objective: We investigated the clinical relevance of non-albumin proteinuria (NAP) in Korean patients with type 2 diabetes (T2D). Research design and methods: We enrolled 883 T2D patients who had both their urinary albumin-to-creatinine ratio (uACR) and protein-to-creatinine ratio (uPCR) measured. We classified the patients into non-proteinuria (NP; uPCR <150 mg/g and uACR <30 mg/g), isolated NAP (iNAP; uPCR ≥150 mg/g and uACR <30 mg/g), and albuminuria (uACR ≥30 mg/g) groups. The associations between uPCR, uACR, and several indices of glucose metabolism were investigated. Results: The glucometabolic pathophysiology of iNAP (96 [10.9%]) group was more associated with a decrease in homeostatic model assessment (HOMA)-beta value (aOR 1.89 [95% CI, 1.21–2,96]) than with an increase in HOMA-insulin resistance (aOR 1.29 [95% CI, 0.83–2.01]). uPCR ≥150 mg/g was also found to have more consistent and stronger association with vascular complications than uACR ≥30 mg/g (aOR 1.44 [95% CI, 1.03–2.02] vs. 1.26 [95% CI, 0.89–1.79]). Conclusions: The nephropathy of iNAP may be mainly attributed to decreased beta cell function. Furthermore, uPCR might be a more sensitive urinary biomarker than uACR for the detection of vascular complications in T2D patients.