What is the treatment for a patient with chronic kidney disease (CKD) and impaired renal function, characterized by elevated urea and creatinine levels?

Treatment of Chronic Kidney Disease with Elevated Urea and Creatinine

For patients with CKD and elevated urea and creatinine, initiate an ACE inhibitor (such as enalapril 5-10 mg daily) or an ARB (such as losartan 50 mg daily, titrated to 100 mg daily) if the patient has hypertension and/or albuminuria ≥30 mg/g creatinine, optimize blood pressure control, restrict dietary protein to 0.8 g/kg/day, and refer to nephrology when eGFR falls below 30 mL/min/1.73 m². 1, 2

Initial Assessment and Staging

Before prescribing treatment, confirm the diagnosis and stage of CKD:

• Measure urinary albumin-to-creatinine ratio (UACR) in a spot urine sample to assess albuminuria, with normal defined as <30 mg/g and elevated as ≥30 mg/g 1, 3
• Calculate eGFR using the CKD-EPI equation (preferred over MDRD), which provides better accuracy especially at eGFR ≥60 mL/min/1.73 m² 3, 4
• Stage the CKD by GFR categories: G3a (45-59), G3b (30-44), G4 (15-29), G5 (<15 mL/min/1.73 m²) and albuminuria categories: A1 (<30), A2 (30-300), A3 (>300 mg/g) 3
• Confirm chronicity by documenting that abnormalities persist for >3 months, as this distinguishes CKD from acute kidney injury 1, 3

Pharmacological Treatment

Renin-Angiotensin System Blockade

ACE inhibitors or ARBs are the cornerstone of CKD treatment when hypertension and/or albuminuria are present:

• For UACR 30-299 mg/g (moderately elevated albuminuria): Use either an ACE inhibitor or ARB in patients with hypertension 1
• For UACR ≥300 mg/g and/or eGFR <60 mL/min/1.73 m²: Strongly recommend ACE inhibitor or ARB regardless of blood pressure 1
• Specific dosing for losartan: Start at 50 mg once daily and titrate to 100 mg once daily to achieve maximum renoprotective benefits, as clinical trials demonstrating kidney protection used these higher doses 2
• Do NOT use ACE inhibitors or ARBs for primary prevention in patients with normal blood pressure, normal UACR (<30 mg/g), and normal eGFR 1

Monitoring During RAS Blockade

Critical monitoring parameters to avoid premature discontinuation:

• Check serum creatinine and potassium within 2-4 weeks of initiation or dose increase 1, 2
• Accept up to 30% increase in serum creatinine within 4 weeks of starting therapy—this is expected and does not indicate harm 1, 2
• Do NOT discontinue for minor creatinine increases (<30%) in the absence of volume depletion 1
• Continue therapy even when eGFR falls below 30 mL/min/1.73 m² unless symptomatic hypotension or uncontrolled hyperkalemia develops 2
• Manage hyperkalemia medically with potassium-lowering measures rather than stopping the ACE inhibitor/ARB when possible 2

Additional Medications for Diabetic CKD

If the patient has type 2 diabetes and diabetic kidney disease:

• Add an SGLT2 inhibitor (such as empagliflozin 10 mg daily or dapagliflozin 10 mg daily) when eGFR >30 mL/min/1.73 m² and/or UACR >300 mg/g for cardiovascular risk reduction 1
• Consider a GLP-1 receptor agonist (such as semaglutide or dulaglutide) in patients at increased cardiovascular risk, as these reduce albuminuria progression and cardiovascular events 1

Blood Pressure Management

Target blood pressure based on albuminuria status:

• For UACR <30 mg/g: Treat to maintain BP consistently ≤140/90 mmHg 1
• For UACR ≥30 mg/g: Treat to maintain BP consistently ≤130/80 mmHg 1
• Optimize blood pressure control to reduce risk or slow progression of CKD 1
• Monitor for postural hypotension regularly when using BP-lowering drugs, especially in elderly patients 1

Dietary Management

Protein restriction is essential in non-dialysis CKD:

• Restrict dietary protein to approximately 0.8 g/kg body weight per day (the recommended daily allowance) for all patients with non-dialysis-dependent CKD 1
• Higher protein intake should be considered for patients on dialysis (typically 1.0-1.2 g/kg/day) since malnutrition is a major problem in dialysis patients 1

Iron and Anemia Management

If anemia develops (hemoglobin <10 g/dL):

• Evaluate iron status before initiating erythropoiesis-stimulating agents (ESAs) 5
• Administer supplemental iron when serum ferritin is <100 mcg/L or transferrin saturation is <20%, as the majority of CKD patients require supplemental iron during ESA therapy 5
• For ESA therapy (epoetin alfa): Start at 50-100 Units/kg three times weekly IV or subcutaneously when hemoglobin is <10 g/dL 5
• Target hemoglobin level: Do NOT exceed 11 g/dL, as higher targets increase risks of death, serious cardiovascular reactions, and stroke 5

Nephrology Referral Criteria

Refer to nephrology at specific thresholds:

• Mandatory referral when eGFR <30 mL/min/1.73 m² (stage G4-G5) 1
• Prompt referral for: Uncertainty about etiology, difficult management issues, rapidly progressing kidney disease, or persistent proteinuria >1 g/day 1
• Consider referral for: Inability to meet BP goals, severe electrolyte abnormalities, or inability to tolerate renal protective medications 1

Common Pitfalls to Avoid

• Don't underdose ACE inhibitors/ARBs: The proven renoprotective benefits were achieved with full doses (e.g., losartan 100 mg daily), not lower doses 2
• Don't stop RAS blockade for mild creatinine increases: Up to 30% elevation is expected and beneficial, not harmful 1, 2
• Don't discontinue prematurely for hyperkalemia: Manage potassium medically before reducing or stopping therapy 2
• Don't over-restrict protein in dialysis patients: They require higher protein intake (>0.8 g/kg/day) to prevent malnutrition 1
• Don't target hemoglobin >11 g/dL with ESAs: This increases mortality and cardiovascular risks 5