In diabetic kidney disease, which biomarker helps assess early risk of progression?

• A. Serum creatinine
• B. Urinary albumin-to-creatinine ratio
• C. Blood urea nitrogen
• D. C-reactive protein

Answer: (B)

Core idea: the earliest signal of kidney damage in diabetes is albumin leaking into the urine. The urinary albumin-to-creatinine ratio detects this microalbuminuria, which occurs before significant loss of kidney function. This makes it a powerful predictor of progression to worse kidney disease and related cardiovascular risk. In contrast, serum creatinine and the resulting eGFR often stay normal until substantial nephron loss has happened, so they are late indicators. Blood urea nitrogen is influenced by hydration and protein intake and isn’t specific for early diabetic kidney damage. C-reactive protein reflects systemic inflammation, not kidney-specific injury in diabetes. So the urinary albumin-to-creatinine ratio best identifies those at risk early on.