Nephropathy is kidney disease. Diabetic nephropathy is kidney damage specifically caused by long-term high blood sugar affecting the small blood vessels of the kidney glomeruli. It affects 30 to 40 percent of patients with diabetes and is the leading cause of end-stage renal disease in the US. Diagnosis relies on urine albumin-to-creatinine ratio and estimated glomerular filtration rate. Treatment — tight glucose control, blood pressure management, ACE inhibitors/ARBs, SGLT2 inhibitors, and lifestyle — can slow or sometimes halt progression. Early stages are sometimes reversible; later stages are managed to delay dialysis or transplant.
Types of Nephropathy
| Type | Cause |
|---|---|
| Diabetic nephropathy | Long-term high blood sugar |
| Hypertensive nephropathy | Long-term high blood pressure |
| Glomerulonephritis | Immune-mediated glomerular inflammation |
| Polycystic kidney disease | Genetic — cysts progressively damage kidneys |
| Analgesic nephropathy | Long-term NSAID or acetaminophen use |
| Lupus nephritis | Systemic lupus erythematosus attacking the kidneys |
| IgA nephropathy | Immune complex deposition |
| Membranous nephropathy | Autoimmune targeting of glomerular basement membrane |
| Amyloid nephropathy | Amyloid protein deposition |
How Diabetic Nephropathy Develops
Stage 1: Hyperfiltration (Early)
- Kidneys temporarily filter more blood than normal
- eGFR may appear elevated
- No symptoms
- Subclinical; detectable only with specialized testing
Stage 2: Normal Albuminuria, Early Structural Change
- Basement membrane thickening begins
- UACR still under 30 mg/g
- eGFR may be at baseline
- Still largely silent
Stage 3: Microalbuminuria (Early Clinical Kidney Disease)
- UACR 30 to 300 mg/g
- eGFR often still normal (greater than 60)
- No symptoms
- Treatment at this stage can slow or reverse progression
Stage 4: Macroalbuminuria (Overt Nephropathy)
- UACR over 300 mg/g
- eGFR often beginning to decline
- May see mild hypertension, edema
- Progression is usually ongoing without treatment
Stage 5: End-Stage Renal Disease (ESRD)
- eGFR under 15 mL/min/1.73m²
- Symptoms: fatigue, swelling, nausea, itching, poor appetite
- Requires dialysis or kidney transplant
- Usually 5 to 10 years after onset of macroalbuminuria without treatment
Diagnostic Tests
Urine Albumin-to-Creatinine Ratio (UACR)
| Value (mg/g) | Category |
|---|---|
| Under 30 | Normal |
| 30 to 300 | Microalbuminuria (moderately increased) |
| Over 300 | Macroalbuminuria (severely increased) |
Estimated Glomerular Filtration Rate (eGFR)
| eGFR (mL/min/1.73m²) | CKD Stage |
|---|---|
| 90+ | Stage 1 (normal/high) |
| 60–89 | Stage 2 (mild decrease) |
| 45–59 | Stage 3a (moderate) |
| 30–44 | Stage 3b (moderate-to-severe) |
| 15–29 | Stage 4 (severe) |
| Under 15 | Stage 5 (kidney failure) |
Annual Screening Recommendations
- All type 2 diabetes patients: annually from diagnosis
- Type 1 diabetes patients: annually starting 5 years after diagnosis
- Pregnant patients with pre-existing diabetes: at each prenatal visit
- Comprehensive metabolic panel and urine test are typically the minimum
Treatment — Evidence-Based Pillars
Glucose Control
- A1C target under 7 percent for most adults (individualized)
- Tight control slows progression especially in stage 2 and 3
- DCCT and UKPDS trials showed significant reduction in nephropathy incidence with intensive control
Blood Pressure Control
- Target under 130/80 mmHg
- More aggressive targets in some populations
- Lifestyle plus medication
ACE Inhibitors or ARBs
- First-line kidney-protective medications
- Lisinopril, ramipril, enalapril (ACEIs); losartan, valsartan, olmesartan (ARBs)
- Reduce albuminuria and slow progression independently of blood pressure
- Indicated for most diabetic nephropathy patients
SGLT2 Inhibitors
- Empagliflozin (Jardiance), dapagliflozin (Farxiga), canagliflozin (Invokana), ertugliflozin (Steglatro)
- Strong evidence for slowing CKD progression and reducing cardiovascular events
- FDA-approved specifically for CKD in diabetes
- Can be added even at low eGFR (now approved down to 25 mL/min/1.73m² in many cases)
Finerenone (Kerendia)
- Non-steroidal mineralocorticoid receptor antagonist
- Approved for CKD in type 2 diabetes
- Reduces cardiovascular and renal events
- Often added when ACE/ARB + SGLT2 are maximized
GLP-1 Receptor Agonists
- Semaglutide and tirzepatide have emerging evidence for kidney benefit
- Weight loss helps insulin resistance and blood pressure
- Less direct renal evidence than SGLT2 inhibitors
Lifestyle
- Weight loss of 5 to 10 percent
- Reduced sodium (under 2.3 g/day) and moderate protein intake
- Smoking cessation (smoking accelerates CKD progression)
- Regular aerobic exercise
- Avoid NSAIDs when possible
When to Refer to a Nephrologist
- eGFR under 30 mL/min/1.73m²
- Rapidly declining eGFR (greater than 5 units per year)
- Unexplained anemia or other CKD complications
- Persistent macroalbuminuria despite treatment
- Complex comorbidities requiring specialized input
- Discussion of dialysis or transplant planning
Related Reading
See our guides on complications and related conditions, prediabetes 101, and our broader treatment hub.
The Bottom Line
Nephropathy is kidney disease; diabetic nephropathy specifically is kidney damage from long-term high blood sugar. It affects up to 40 percent of diabetes patients and is the leading cause of kidney failure in the US. Diagnosis uses urine albumin and eGFR. Treatment — tight glucose control, blood pressure management, ACE inhibitors or ARBs, SGLT2 inhibitors, and lifestyle — can slow or halt progression, especially in early stages. Annual screening is essential for all patients with diabetes. With early recognition and evidence-based treatment, many patients avoid progression to end-stage renal disease. If your UACR or eGFR are abnormal, work closely with your clinician and consider nephrology referral.
