What is the approach to managing a patient with impaired renal function, specifically an estimated Glomerular Filtration Rate (eGFR) of 19?

Management of eGFR 19 mL/min/1.73 m²

A patient with eGFR 19 requires immediate nephrology referral, preparation for renal replacement therapy, discontinuation of metformin, aggressive blood pressure control with ACE inhibitors or ARBs, and comprehensive management of CKD complications including anemia, metabolic acidosis, and mineral bone disease. 1

Immediate Nephrology Referral

Refer to nephrology immediately—this is non-negotiable at eGFR 19. 1 This represents Stage 4 CKD (severely decreased kidney function), and consultation at this stage reduces costs, improves quality of care, and delays dialysis. 2, 1 The patient is approaching Stage 5 CKD (eGFR <15), making preparation for renal replacement therapy urgent. 1

Renal Replacement Therapy Planning

• Begin patient education now about dialysis and transplantation options. 1 Dialysis initiation should be considered when GFR falls below 15 mL/min/1.73 m², though certain complications may justify earlier initiation. 1
• Consider vascular access planning (arteriovenous fistula creation) as this takes months to mature. 1
• Kidney transplantation or home dialysis may be optimal before reaching Stage 5 CKD. 1

Critical Medication Adjustments

Antidiabetic Medications (if diabetic):

• Metformin: STOP IMMEDIATELY—contraindicated at eGFR <30. 2, 1 The FDA guidance is clear on this point.
• Insulin: Reduce total daily dose by 35-50% due to decreased renal clearance and reduced gluconeogenesis. 1
• SGLT2 inhibitors: Canagliflozin maximum 100 mg daily; may continue for kidney and cardiovascular benefit until dialysis. 1 Dapagliflozin not recommended for glucose lowering at this eGFR but may be used at 10 mg for heart failure or CKD indications if eGFR is 25-45. 1
• DPP-4 inhibitors: Sitagliptin 25 mg daily, alogliptin 6.25 mg daily, saxagliptin maximum 2.5 mg daily. 1
• GLP-1 agonists: Exenatide is contraindicated; lixisenatide should be avoided if eGFR <15; liraglutide, dulaglutide, and semaglutide require no dose adjustment but monitor eGFR closely. 1
• Sulfonylureas: Avoid glyburide entirely; consider alternatives to glimepiride. 1

Other Medications:

• Avoid nephrotoxins: NSAIDs, proton-pump inhibitors (chronic use), and iodinated contrast. 3
• Adjust antibiotic dosing based on renal function. 4

Blood Pressure Management

• Target systolic BP <130 mmHg and diastolic BP <80 mmHg. 1
• Use ACE inhibitors or ARBs as first-line agents for blood pressure control and kidney protection, particularly if albuminuria is present. 2, 1 These medications are strongly recommended for UACR ≥300 mg/g or eGFR <60. 2
• Monitor serum creatinine and potassium closely when using ACE inhibitors, ARBs, or diuretics. 2
• Do NOT combine ACE inhibitors with ARBs—this increases adverse events (hyperkalemia, AKI) without additional benefit. 2

Monitoring Frequency

• Monitor creatinine, eGFR, urinary albumin excretion, and potassium twice yearly at minimum. 1
• Increase to quarterly or more often if rapid progression, new medications, or clinical status changes. 1
• Monitor electrolytes and renal function daily if administering IV fluids. 5

Screening and Managing CKD Complications

At eGFR 19, multiple complications require active management:

• Anemia: Screen and treat per nephrology guidance. 4
• Secondary hyperparathyroidism: Screen and manage as part of CKD-mineral bone disease. 1
• Metabolic acidosis: Evaluate and correct—commonly develops at this level of kidney function. 1, 3
• Hyperkalemia: Monitor closely, especially with ACE inhibitors/ARBs. 2
• Hyperphosphatemia and vitamin D deficiency: Screen and manage. 4

Glycemic Control (if diabetic)

• Target HbA1c <7.0% for most patients, though higher targets may be appropriate for severe comorbidities, limited life expectancy, or high hypoglycemia risk. 1
• Monitor HbA1c twice yearly, increasing to quarterly if not at target or therapy changes. 1

Dietary Management

• Protein intake: 0.8 g/kg body weight per day (the recommended daily allowance for non-dialysis CKD). 2 Do not restrict below this level as it doesn't improve outcomes. 2
• Sodium restriction: <2,300 mg/day to control blood pressure and reduce cardiovascular risk. 2
• Potassium restriction may be necessary to control serum potassium, particularly with ACE inhibitor/ARB use. 2

Fluid Management Precautions

• Consult nephrology before administering IV fluids—patients with eGFR 19 are at significantly increased risk of fluid overload and further kidney damage. 5
• Monitor daily for signs of fluid overload when IV fluids are necessary. 5
• Diuretic use must be carefully considered as patients are approaching dialysis threshold. 5

Cardiovascular Risk Reduction

• Prescribe statins for cardiovascular risk reduction. 4
• Recognize that CKD markedly increases cardiovascular risk—treat aggressively. 2, 4

Common Pitfalls to Avoid

• Do not delay nephrology referral—waiting until eGFR <15 is too late for optimal preparation. 2, 1
• Do not continue metformin "just a little longer"—lactic acidosis risk is real at this eGFR. 2, 1
• Do not give IV fluids liberally—volume overload can precipitate acute decompensation. 5
• Do not ignore medication dose adjustments—many drugs accumulate at this level of renal function. 4
• Do not restrict protein excessively—this doesn't help and may cause malnutrition. 2