When should a diabetic patient be referred to nephrology?

When to Refer a Diabetic Patient to Nephrology

Refer diabetic patients to nephrology when eGFR falls below 30 mL/min/1.73 m² (Stage 4 CKD or worse), or promptly for rapidly declining kidney function, uncertain etiology, or difficult management issues. 1

Absolute Indications for Nephrology Referral

eGFR-Based Criteria

• eGFR <30 mL/min/1.73 m² is a mandatory referral threshold regardless of albuminuria status 1
• This applies to all CKD stages G4 (eGFR 15-29) and G5 (eGFR <15) 1

Progressive Kidney Function Decline

• Continuously decreasing eGFR with continuously increasing urinary albumin levels warrants referral even if eGFR remains >30 1
• Rapid GFR decline (sustained decline >5 mL/min/1.73 m² per year confirmed over 6-12 months) requires prompt nephrology consultation 2

Prompt Referral Situations

Diagnostic Uncertainty

Refer immediately when the etiology of kidney disease is unclear, including: 1

• Absence of retinopathy in type 1 diabetes with kidney disease (rare presentation suggesting alternative diagnosis) 1
• Active urinary sediment (red/white blood cells or cellular casts) 1
• Gross hematuria with albuminuria 1
• Rapidly increasing albuminuria 1
• Duration of type 1 diabetes <10 years with significant kidney disease 1

Difficult Management Issues

• Resistant hypertension despite multiple agents 1
• Anemia requiring evaluation 1
• Secondary hyperparathyroidism or metabolic bone disease 1
• Persistent electrolyte disturbances (particularly hyperkalemia) 1

Risk-Stratified Referral Based on Combined eGFR and Albuminuria

The 2020 American Diabetes Association guidelines provide a comprehensive grid system for referral decisions: 1

Refer Category (Nephrology Consultation Recommended)

• eGFR 45-59 (G3a) with albuminuria ≥300 mg/g 1
• eGFR 30-44 (G3b) with any level of albuminuria 1
• eGFR 15-29 (G4) at all albuminuria levels (may discuss with nephrology service depending on local arrangements) 1
• eGFR <15 (G5) at all albuminuria levels 1

Consider Referral

• eGFR 60-89 (G2) with albuminuria ≥300 mg/g (marked with "Refer*" indicating clinician discretion) 1
• eGFR ≥90 (G1) with albuminuria ≥300 mg/g (marked with "Refer*") 1

Monitoring Frequency Before Referral

For patients not yet meeting absolute referral criteria: 1

• eGFR 45-59 with moderate albuminuria (30-299 mg/g): Monitor twice yearly 1
• eGFR 30-44: Monitor three times yearly 1
• eGFR 15-29: Monitor four times yearly 1

Important Caveats

Type 2 Diabetes Considerations

• CKD may be present at diagnosis of type 2 diabetes, so don't rely solely on diabetes duration 1
• Retinopathy is only moderately sensitive and specific for diabetic kidney disease in type 2 diabetes—its absence does not exclude diabetic nephropathy 1, 3
• Reduced eGFR without albuminuria is increasingly common in type 2 diabetes and still represents diabetic kidney disease 1, 4

Don't Confuse with Acute Kidney Injury

• Small creatinine elevations up to 30% from baseline with ACE inhibitors or ARBs are expected and should not trigger referral 1
• Do not discontinue renin-angiotensin system blockade for mild-to-moderate creatinine increases (<30%) without signs of volume depletion 1

Earlier Referral May Be Beneficial

• The 2015 guidelines noted that consultation when Stage 4 CKD develops (eGFR <30) reduces cost, improves quality of care, and delays dialysis 1
• However, primary care providers should not delay patient education about progressive kidney disease and treatment benefits while awaiting nephrology consultation 1

Confirm Albuminuria Before Acting

• Two of three UACR specimens collected within 3-6 months should be abnormal before confirming high albuminuria due to >20% biological variability 1
• Transient elevations can occur with exercise within 24 hours, infection, fever, heart failure, marked hyperglycemia, menstruation, or severe hypertension 1