What is the difference between Diabetic Kidney Disease (DKD) and Diabetic Microvascular Nephropathy (DMN)?

Difference Between DKD and Diabetic Nephropathy

Diabetic Kidney Disease (DKD) is a clinical diagnosis made at the bedside based on laboratory values, signs, and symptoms, while diabetic nephropathy is a tissue diagnosis requiring kidney biopsy to confirm characteristic pathologic glomerular lesions. 1

Key Distinctions

DKD (Diabetic Kidney Disease)

• Clinical diagnosis that describes the development of chronic kidney disease in patients with diabetes based on:
  • Persistent albuminuria (UACR >30 mg/g) for at least 3 months 1
  • Persistent reduction in eGFR below 60 mL/min/1.73 m² for at least 3 months 1
  • Or both abnormalities present 1
• Does not require biopsy confirmation 1
• Represents a presumptive diagnosis of kidney disease caused by diabetes 1

Diabetic Nephropathy (Also Called Diabetic Glomerulopathy)

• Tissue diagnosis requiring kidney biopsy 1
• Refers specifically to characteristic pathologic glomerular lesions caused by diabetes 1
• Includes findings such as:
  • Nodular glomerulosclerosis 1
  • Mesangial expansion 2
  • Glomerular basement membrane thickening 3
  • Tubulointerstitial fibrosis 3

Critical Clinical Implication

This distinction matters because up to 30% of patients with a clinical diagnosis of DKD actually have other causes of chronic kidney disease on kidney biopsy. 1, 4 These alternative diagnoses include:

• Minimal change disease 1, 4
• Primary focal segmental glomerulosclerosis 1, 4
• Polycystic kidney disease 1, 4
• Other glomerular pathologies that may coexist with or mimic diabetic changes 5

When to Suspect Non-Diabetic Causes

Consider kidney biopsy when patients present with: 1

• Absence of diabetic retinopathy 1
• Low or rapidly decreasing GFR 1
• Rapidly increasing proteinuria or nephrotic syndrome 1
• Refractory hypertension 1
• Active urinary sediment 1

• 30% reduction in GFR within 2-3 months after starting ACE inhibitor or ARB 1

• Type 1 diabetes of less than 10 years duration with albuminuria 1

Practical Management Approach

In clinical practice, use the term DKD for patients with diabetes and kidney disease unless biopsy-proven pathology exists. 1 The management approach remains similar regardless of terminology:

• SGLT2 inhibitors for kidney and cardiovascular protection 1, 2
• GLP-1 receptor agonists for additional benefits 1, 2
• ACE inhibitors or ARBs for blood pressure control and proteinuria reduction 2
• Optimal glycemic control 2

Note: The term "diabetic microvascular nephropathy (DMN)" is not standard medical terminology in current guidelines. 1 If this term is being used locally, it likely refers to the same concept as diabetic nephropathy—the microvascular pathologic changes in the kidney caused by diabetes.