What is the appropriate management for a patient with impaired renal function?

Management of Stage 3b Chronic Kidney Disease (eGFR 43 mL/min/1.73m²)

This patient requires immediate comprehensive CKD management with blood pressure optimization, nephrology referral, medication review, and monitoring for CKD complications, as the eGFR of 43 mL/min/1.73m² places them in Stage 3b CKD with significantly increased risk for progression and cardiovascular events. 1

Immediate Actions Required

Assess for CKD Complications

• Screen immediately for electrolyte abnormalities (potassium, calcium, phosphorus), metabolic acidosis, anemia (hemoglobin/hematocrit), and metabolic bone disease (PTH, vitamin D). 1, 2
• Measure 25(OH) vitamin D levels; if <30 ng/mL, administer vitamin D2 50,000 units orally monthly for 6 months. 1
• If corrected serum calcium remains <8.5 mg/dL after addressing phosphorus, provide elemental calcium 1 g/day between meals or at bedtime. 1
• Monitor for anemia and consider erythropoietin therapy if hemoglobin is low despite adequate iron stores. 1

Measure Albuminuria

• Obtain spot urine albumin-to-creatinine ratio (ACR) immediately to determine prognosis and guide blood pressure targets. 1, 2
• ACR ≥30 mg/g indicates significantly increased risk for CKD progression and cardiovascular events. 1

Medication Review

• Discontinue all nephrotoxic agents immediately, particularly NSAIDs, which are contraindicated in patients with impaired renal function. 3, 4
• Review and adjust doses of all renally cleared medications based on eGFR of 43 mL/min/1.73m². 1, 5
• Avoid or use extreme caution with contrast media; if required, calculate maximum contrast dose (contrast volume/eGFR ratio) and provide prophylaxis with isotonic saline or sodium bicarbonate hydration. 1, 2

Blood Pressure Management

Target Blood Pressure

• If ACR <30 mg/g: target BP ≤140/90 mmHg. 2
• If ACR ≥30 mg/g: target BP ≤130/80 mmHg. 1, 2
• Check BP at every clinic visit, which should occur at least every 3 months. 1

Antihypertensive Therapy

• Initiate ACE inhibitor or ARB as first-line agent, particularly if albuminuria is present. 1
• For ACE inhibitors (e.g., ramipril): start at 1.25 mg daily with eGFR <30 mL/min; maximum dose 5 mg/day. 1
• Uptitrate to maximally tolerated doses to reduce proteinuria if ACR >300 mg/g. 2
• Monitor serum creatinine and potassium within 1-2 weeks after initiation or dose changes; accept up to 20% increase in creatinine if stable thereafter. 1

Hyperkalemia Risk Management

• Monitor potassium closely when using ACE inhibitors/ARBs, especially with eGFR <45 mL/min/1.73m². 1
• Educate patient to avoid potassium supplements, potassium-based salt substitutes, and high-potassium foods. 1
• If potassium >5.5 mmol/L, reduce or discontinue potassium supplements and consider dose reduction of RAAS inhibitors. 1

Nephrology Referral

Referral Criteria

• Refer to nephrology now, as eGFR <45 mL/min/1.73m² meets criteria for specialist evaluation. 1, 4
• The 2-year kidney failure risk with eGFR 43 mL/min/1.73m² warrants multidisciplinary care planning. 1
• Early referral allows for timely preparation for potential kidney replacement therapy and transplant evaluation. 1

Transplant Evaluation

• If patient is willing and has acceptable surgical risk, initiate transplant evaluation now. 1
• Preserve veins suitable for vascular access (avoid venipuncture in non-dominant arm). 1

Monitoring Strategy

Laboratory Monitoring Every 3 Months

• Serum creatinine, eGFR, electrolytes (sodium, potassium, bicarbonate), calcium, phosphorus. 1, 2
• Spot urine ACR to assess proteinuria trends. 1, 2
• Body weight and serum albumin to monitor nutritional status. 1

Define Disease Progression

• Progression = change in GFR category plus ≥25% decline in eGFR from baseline. 2
• If progression occurs, intensify treatment and increase monitoring frequency. 2

Lipid Monitoring

• Monitor fasting lipid panel (total cholesterol, LDL, HDL, triglycerides) every 3 months. 1
• Target LDL <100 mg/dL and non-HDL cholesterol <130 mg/dL. 1
• Treat fasting triglycerides ≥500 mg/dL. 1

Cardiovascular Risk Reduction

Statin Therapy

• Initiate statin therapy for cardiovascular risk reduction; simvastatin requires dose caution (≤10 mg) with eGFR <30 mL/min. 1, 4

Additional Measures

• Encourage smoking cessation, regular moderate-intensity physical activity (150 minutes/week), and achieve BMI 20-25 kg/m². 1, 2
• If diabetic, target HbA1c of 7% with careful selection of antidiabetic agents safe in CKD. 1, 2

Nutritional Management

Dietary Modifications

• Restrict sodium to <2 g per day. 2
• Adopt plant-based diet with diverse, healthy foods. 1
• If body weight decreases >5% unintentionally or albumin decreases >0.3 g/dL or is <4.0 g/dL (Bromo-Cresol-Green assay), evaluate for malnutrition and provide dietary counseling. 1

Critical Pitfalls to Avoid

Nephrotoxin Exposure

• Never use NSAIDs in this patient—they are contraindicated with impaired renal function and can precipitate acute renal decompensation. 3, 4
• Avoid aminoglycosides and other nephrotoxic antibiotics unless absolutely necessary with dose adjustment. 2

Contrast-Induced Nephropathy

• If contrast imaging is required, provide prophylactic hydration with isotonic saline or sodium bicarbonate (1.26%) starting 1 hour before procedure. 1
• Minimize contrast volume and use iso-osmolar or low-osmolar agents. 1
• Assess creatinine up to day 3 post-contrast to detect contrast-induced nephropathy. 1

Medication Dosing Errors

• Do not use standard doses of renally cleared medications—adjust all doses based on eGFR of 43 mL/min/1.73m². 1, 5
• Anticoagulants (enoxaparin, fondaparinux, bivalirudin) require dose adjustment or are contraindicated with eGFR <30 mL/min. 1, 5

Delayed Nephrology Referral

• Do not delay nephrology referral—eGFR <45 mL/min/1.73m² requires specialist involvement for optimal outcomes. 1, 4, 6