What is the treatment for proteinuria?

Treatment of Proteinuria

The first-line treatment for proteinuria is an ACE inhibitor or ARB, which should be initiated even in normotensive patients with albuminuria to reduce proteinuria to <1 g/day or as low as possible. 1 These medications have demonstrated significant antiproteinuric effects and can slow the progression of kidney disease.

Pharmacological Management

Renin-Angiotensin System (RAS) Blockade

• ACE inhibitors or ARBs:

  • Start with standard doses and titrate as needed
  • Monitor serum creatinine and potassium within 1-2 weeks after initiating or increasing dose
  • A modest increase in serum creatinine (up to 30%) is acceptable
  • Discontinue if kidney function continues to worsen or if refractory hyperkalemia develops 1

• Losartan has been specifically shown to:

  • Reduce proteinuria by an average of 34% (effect evident within 3 months)
  • Reduce the rate of decline in glomerular filtration rate by 13%
  • Reduce the risk of doubling of serum creatinine by 25% and end-stage renal disease by 29% in diabetic nephropathy 2

• Dual RAS blockade (ACE inhibitor + ARB):

  • May provide additional proteinuria reduction
  • Use cautiously due to increased risk of hyperkalemia and acute kidney injury 1

Additional Antihypertensive Agents

• Non-dihydropyridine CCBs (diltiazem, verapamil) have antiproteinuric effects
• Avoid amlodipine in patients with glomerular hypertension 1
• Diuretics should be added if blood pressure targets are not achieved with RAS blockade 3

Blood Pressure Management

• Target blood pressure based on proteinuria level:

  • 1 g/day proteinuria: <125/75 mmHg

  • <1 g/day proteinuria: <130/80 mmHg
  • Pediatric patients: ≤50th percentile for age, sex, and height 1

Dietary Interventions

• Protein intake: Target 0.8 g/kg body weight per day

  • Avoid excessive protein restriction (<0.8 g/kg/day) as there's no conclusive evidence of additional benefit
  • Higher protein intake (>1.3 g/kg/day) is associated with increased proteinuria and decreased renal function 1

• Sodium restriction: Limit to less than 2 g/day to help control blood pressure 1

• Diet composition: Emphasize vegetables, fruits, whole grains, fiber, legumes, and plant-based proteins 1

Lifestyle Modifications

• Physical activity: Moderate-intensity activity for at least 150 minutes per week
• Weight management: Normalize weight if overweight or obese 1

Monitoring Response to Treatment

• Monitor albumin:creatinine ratio every 3-6 months to assess treatment response
• Goal: Reduce proteinuria to <1 g/day or as low as possible
• Monitor blood pressure at every clinic visit
• Assess medication adherence at each visit 1

Special Considerations

Diabetic Nephropathy

• For patients with type 2 diabetes and nephropathy, losartan has shown significant benefits:
  • 16% risk reduction in the composite endpoint of doubling of serum creatinine, end-stage renal disease, or death
  • Proteinuria reduction evident within 3 months of starting therapy 2

Lupus Nephritis

• Treatment should aim for proteinuria <0.5–0.7 g/24 hours by 12 months (complete clinical response)
• At least 50% reduction in proteinuria (partial clinical response) by 6 months
• For nephrotic-range proteinuria, these timeframes may be extended by 6–12 months 4

When to Refer to Nephrology

Refer patients to nephrology if they have:

• Persistent proteinuria >1g/day
• GFR <30 mL/min/1.73 m²
• Abrupt sustained decrease in eGFR >20%
• Inability to tolerate renoprotective medications
• Uncertainty about diagnosis
• Risk of kidney failure within 1 year is 10-20% or higher 1

Common Pitfalls to Avoid

1. Delaying treatment: Early intervention with ACE inhibitors or ARBs is crucial to prevent progressive kidney damage
2. Inadequate blood pressure control: Failing to achieve target blood pressure goals based on proteinuria level
3. Insufficient monitoring: Not checking serum creatinine and potassium after initiating RAS blockade
4. Overlooking non-pharmacological interventions: Dietary and lifestyle modifications are important adjuncts to medication
5. Stopping ACE inhibitors/ARBs prematurely: A modest increase in serum creatinine (up to 30%) is expected and acceptable

Remember that proteinuria is not just a marker of kidney disease but also contributes to progressive kidney damage, making aggressive treatment essential for preserving renal function.