Diabetic Nephropathy: Stages

Key points

• The old five-stage diabetic-nephropathy model based on hyperfiltration → silent phase → microalbuminuria → overt proteinuria → ESRD is outdated and should not be used as the primary modern classification.
• Modern diabetic kidney disease assessment uses eGFR plus albuminuria (ACR) categories. A1 = <3 mg/mmol, A2 = 3–30 mg/mmol and A3 = >30 mg/mmol; CKD G categories are assessed separately.
• Moderately increased albuminuria (A2) is ACR 3–30 mg/mmol. It should be confirmed when appropriate because transient albuminuria can occur with exercise, infection, hyperglycaemia, hypertension and other conditions.
• Severely increased albuminuria (A3) is ACR >30 mg/mmol. Persistent A3 albuminuria carries high kidney and cardiovascular risk and should prompt appropriate kidney-protective management and specialist referral when guideline criteria are met.
• Diabetic kidney disease can progress to falling eGFR and kidney failure , but albuminuria and eGFR do not always progress in a fixed sequence. Current management includes BP/proteinuria control and, where eligible, kidney-protective therapies such as ACEi/ARB and SGLT2 inhibitors.
• MRCP discriminator: diabetic patient + persistent ACR ≥3 mg/mmol → albuminuric diabetic kidney disease/CKD if chronicity and other criteria are met; classify with both G and A categories.
• Current treatment clue: ACEi/ARB is particularly important with albuminuria/hypertension, and SGLT2 inhibitors provide renal protection in eligible patients.