How to manage impaired renal function with a creatinine level of 1.12 and an eGFR of 57?

Management of Creatinine 1.12 mg/dL and eGFR 57 mL/min/1.73 m²

This represents Stage 3a chronic kidney disease (CKD) requiring nephrology evaluation, medication adjustments, and cardiovascular risk reduction strategies. 1

Confirm the Diagnosis

Before proceeding with CKD management, verify that this represents true kidney disease rather than measurement artifact:

• Repeat eGFR and creatinine within 3 months to confirm persistence, as a single measurement is insufficient for CKD diagnosis 1
• Obtain urinary albumin-to-creatinine ratio (UACR) from a spot urine sample, as albuminuria >30 mg/g confirms kidney damage even at higher eGFR levels 1
• Exclude exogenous creatinine sources including creatine supplements (creatine ethyl ester), which can falsely elevate serum creatinine and reduce calculated eGFR without true kidney disease 2, 3
• Consider cystatin C measurement if eGFR 45-59 mL/min/1.73 m² without albuminuria or other markers of kidney damage, as this confirms CKD in approximately two-thirds of cases and identifies those at markedly elevated risk for death and cardiovascular disease 1

Immediate Medication Review

All renally cleared medications must be dose-adjusted for eGFR 57 mL/min/1.73 m² 4:

• Discontinue or avoid nephrotoxic agents: NSAIDs, aminoglycosides, and minimize contrast dye exposure (use only with adequate hydration when absolutely necessary) 4
• Metformin requires caution at this eGFR level: While not contraindicated (contraindication threshold is eGFR <30 mL/min/1.73 m²), initiation is not recommended in patients with eGFR 30-45 mL/min/1.73 m², and more frequent monitoring is warranted as eGFR approaches 45 mL/min/1.73 m² due to lactic acidosis risk 5
• Review all medications for appropriate renal dosing adjustments using standard references 4

Assess Cardiovascular Risk

CKD itself is an independent cardiovascular disease risk factor, with eGFR <60 mL/min/1.73 m² conferring approximately 16% increased cardiovascular mortality 1:

• Measure blood pressure and target <130/80 mmHg (or <125/75 mmHg if proteinuria present), as lower systolic blood pressure correlates with slower renal disease progression 1
• Initiate ACE inhibitor or ARB if albuminuria is present (UACR >30 mg/g), as these agents slow CKD progression in patients with proteinuria 1
• Assess lipid profile and manage dyslipidemia aggressively given elevated cardiovascular risk 1
• Screen for diabetes if not already diagnosed, as hyperglycemia accelerates kidney disease progression 1

Monitor for CKD Complications

At eGFR 57 mL/min/1.73 m², metabolic complications may already be present 6:

• Check complete blood count for anemia, which can occur at eGFR levels higher than previously recognized, particularly in elderly patients 6
• Measure serum calcium, phosphorus, parathyroid hormone, and vitamin D to screen for mineral bone disease 4
• Assess serum bicarbonate and consider supplementation if <22 mEq/L to manage metabolic acidosis 4
• Monitor serum potassium and restrict dietary potassium if hyperkalemia develops; avoid potassium-sparing medications 4

Establish Monitoring Schedule

Assess eGFR and UACR at least annually, with more frequent monitoring (every 3-6 months) warranted given the eGFR is in the 45-59 mL/min/1.73 m² range 1:

• Identify progression risk factors: cause of CKD, degree of albuminuria, age, race/ethnicity, elevated blood pressure, hyperglycemia, dyslipidemia, smoking, obesity, cardiovascular disease history, and ongoing nephrotoxic exposures 1
• Define progression as sustained decline in eGFR >5 mL/min/1.73 m² per year or >25% reduction from baseline, though even smaller declines are associated with increased mortality and end-stage renal disease risk 1

Nephrology Referral Considerations

While not requiring urgent nephrology referral at this stage, consider consultation if 4:

• Rapidly progressive decline in eGFR (>5 mL/min/1.73 m² per year) 1
• Significant albuminuria (UACR >300 mg/g) or nephrotic-range proteinuria 1
• Active urinary sediment (red/white blood cells, cellular casts) suggesting glomerulonephritis 1
• Uncertain etiology of kidney disease 1
• Difficult management issues including refractory hypertension, anemia, or mineral bone disease 4

Address Modifiable Risk Factors

Lifestyle modifications are essential to slow CKD progression 1:

• Smoking cessation is mandatory, as smoking accelerates kidney disease 1
• Weight reduction if obese (BMI >30 kg/m²) 1
• Sodium restriction to <2 grams daily to optimize blood pressure control 4
• Protein intake moderation may be considered, though specific recommendations vary 1

Common Pitfalls to Avoid

• Do not rely solely on serum creatinine to assess kidney function, as it reflects muscle mass, dietary intake, and creatine supplementation in addition to GFR 2, 7, 3
• Do not assume normal kidney function based on "normal" creatinine (1.12 mg/dL), as significant GFR reduction can occur with creatinine values in the traditional normal range, particularly in elderly patients, women, and those with low muscle mass 1
• Do not use 24-hour urine collections for creatinine clearance, as spot UACR is more accurate and practical 1
• Do not delay ACE inhibitor/ARB therapy if albuminuria is present, even if blood pressure is normal, as these agents provide renoprotection independent of blood pressure lowering 1
• Do not withhold contrast studies absolutely, but assess risk using validated scoring systems (eGFR 40-60 mL/min scores 2 points) and ensure adequate hydration 1