What is the treatment for impaired renal function with elevated serum creatinine, decreased GFR, and microalbuminuria?

Treatment for Chronic Kidney Disease Stage 3b with Microalbuminuria

Based on your laboratory values (creatinine 1.34 mg/dL, GFR 44 mL/min/1.73 m², microalbumin 1.2 mg/dL), you have CKD Stage 3b and require immediate initiation of an ACE inhibitor or ARB, aggressive blood pressure control to <130/80 mmHg, optimization of glycemic control if diabetic, and nephrology referral.

Immediate Pharmacologic Intervention

Start either an ACE inhibitor or angiotensin receptor blocker (ARB) immediately, regardless of blood pressure status. 1

• In patients with GFR <60 mL/min/1.73 m² and any degree of albuminuria, ACE inhibitors or ARBs are strongly recommended to slow progression of nephropathy 1
• ARBs have demonstrated specific benefit in patients with elevated serum creatinine (>1.5 mg/dL in males) and proteinuria, reducing progression to end-stage renal disease by 28.6% 2
• If one class is not tolerated due to cough (ACE inhibitor) or other side effects, substitute with the other class 1
• Critical monitoring requirement: Check serum potassium and creatinine within 1-2 weeks after initiation, as hyperkalemia and acute rises in creatinine can occur 1, 2

Blood Pressure Management

Target blood pressure should be <130/80 mmHg (some guidelines suggest <130/85 mmHg). 1

• Optimize blood pressure control aggressively, as this is A-level evidence for slowing CKD progression 1
• If ACE inhibitor/ARB alone does not achieve target, add additional agents (diuretics, calcium channel blockers, beta-blockers) 1
• Avoid non-dihydropyridine calcium channel blockers (non-DCCBs) as initial therapy, as they are less effective than ACE inhibitors/ARBs in slowing nephropathy progression 1

Glycemic Control (If Diabetic)

If you have diabetes, optimize glucose control to HbA1c <7% (or individualized target based on comorbidities). 1

• Intensive glycemic control has A-level evidence for reducing risk and slowing progression of nephropathy 1
• Consider SGLT2 inhibitors as they have additional renoprotective benefits beyond glucose control 1

Dietary Modifications

Restrict dietary protein intake to 0.8 g/kg body weight/day (approximately 10% of daily calories). 1

• This represents the adult Recommended Dietary Allowance for protein 1
• Further restriction to 0.6 g/kg/day may be considered if GFR continues to decline, but monitor closely for protein malnutrition 1
• Work with a registered dietitian experienced in diabetic and renal nutrition to design appropriate meal plans 1
• Implement sodium restriction and phosphate restriction as standard modalities 1

Nephrology Referral

You require prompt referral to a nephrologist now, as your GFR is <60 mL/min/1.73 m². 1

• Guidelines recommend nephrology referral when GFR falls to <60 mL/min/1.73 m² 1
• Early referral reduces cost, improves quality of care, and delays need for dialysis 1
• Referral is particularly important given your GFR of 44 mL/min/1.73 m² (Stage 3b), which carries significantly different outcomes than Stage 3a 3

Monitoring Requirements

Establish the following monitoring schedule:

• Serum creatinine, potassium, and eGFR: Check 1-2 weeks after starting ACE inhibitor/ARB, then every 3 months 1, 2
• Urine albumin-to-creatinine ratio: Monitor every 3-6 months to assess treatment response 1
• Blood pressure: Monitor at every visit, with home monitoring if possible 1
• Accept up to 30% increase in serum creatinine after starting ACE inhibitor/ARB, as this represents hemodynamic changes rather than kidney damage 1

Additional Considerations

Avoid nephrotoxic agents and situations:

• NSAIDs (including COX-2 inhibitors) can cause acute deterioration of renal function and should be avoided 2
• Radiocontrast media are particularly nephrotoxic; ensure adequate hydration before any contrast procedures 1
• Do not combine ACE inhibitors with ARBs, as dual RAS blockade increases risks of hyperkalemia and acute kidney injury without additional benefit 2
• Avoid aliskiren entirely in patients with diabetes and renal impairment 2

Cardiovascular Risk Reduction

Recognize that your CKD Stage 3b markedly increases cardiovascular risk. 1, 4

• Implement comprehensive cardiovascular risk management including lipid control, antiplatelet therapy if indicated, smoking cessation, and exercise 2
• Your reduced GFR is a stronger predictor of cardiovascular events than microalbuminuria alone 5, 4

Common Pitfalls to Avoid

• Do not delay ACE inhibitor/ARB initiation waiting for blood pressure to rise, as renoprotection occurs independent of blood pressure effects 1
• Do not stop ACE inhibitor/ARB for modest creatinine increases (<30% rise); this is expected and acceptable 1
• Do not use serum creatinine alone to assess kidney function; always calculate eGFR and monitor albuminuria 1, 3
• Do not assume normal kidney function based on "normal" creatinine of 1.34 mg/dL; your GFR of 44 indicates significant impairment 3