What is the management plan for a patient with impaired renal function, specifically a Glomerular Filtration Rate (GFR) of 32?

Management of GFR 32 mL/min/1.73 m²

A patient with GFR 32 mL/min/1.73 m² has Stage 3b-4 chronic kidney disease and requires immediate referral to nephrology, comprehensive monitoring every 3 months, initiation of renal replacement therapy planning, strict blood pressure control with ACE inhibitors or ARBs, and management of metabolic complications including anemia, bone mineral disorders, and acidosis. 1, 2

Immediate Actions Required

Nephrology Referral

• Refer to specialist kidney care services immediately as GFR <30 mL/min/1.73 m² is an absolute indication for nephrology consultation 1, 2
• This referral is critical to optimize management and prepare for potential renal replacement therapy 1

Begin Renal Replacement Therapy Discussions

• Start counseling about modality of RRT (hemodialysis, peritoneal dialysis, transplantation) now as this is recommended for all patients with GFR <30 mL/min/1.73 m² 1, 2
• If the patient is willing to have a renal transplant, initiate transplant evaluation immediately 1
• If hemodialysis is chosen, preserve veins suitable for vascular access placement (avoid venipuncture and IV lines in non-dominant arm) 1

Monitoring Schedule (Every 3 Months)

Renal Function

• Measure GFR and albuminuria every 3 months to monitor disease progression 1, 2
• Check serum creatinine at each visit 1

Blood Pressure

• Check blood pressure at every clinic visit (minimum every 3 months) 1, 2
• Target systolic BP <130 mmHg and diastolic <80 mmHg 1

Nutritional Status

• Measure body weight and serum albumin every 3 months 1, 2
• If unintentional weight loss >5% or albumin decreases >0.3 g/dL or is <4.0 g/dL (Bromo-Cresol-Green assay), evaluate for causes and provide dietary counseling 1

Metabolic Parameters

• Check serum bicarbonate every 3 months; treat if <22 mmol/L 1, 2
• Measure serum calcium and phosphorus every 3 months 1, 2
• Check intact parathyroid hormone (iPTH) at baseline and every 3 months if calcium/phosphorus abnormal 1, 2

Hematologic Monitoring

• Check hemoglobin every 3 months 1, 2
• If hemoglobin <12 g/dL (women) or <13 g/dL (men), perform complete anemia workup including iron studies 1, 2

Lipid Monitoring

• Monitor lipid profile (triglycerides, LDL, HDL, total cholesterol) regularly 1, 2

Blood Pressure Management

First-Line Therapy

• Use ACE inhibitor or ARB as first-line antihypertensive agent 1, 2
• Titrate to maximally tolerated dose for both blood pressure control and proteinuria reduction 1

Important Caveats

• Monitor for creatinine elevation after initiating RAS inhibitors; consider dose reduction or discontinuation if creatinine rises >30% 1
• Monitor potassium levels closely; use potassium-wasting diuretics or potassium-binding agents if hyperkalemia develops to allow continued RAS inhibitor use 1
• Instruct patients to hold ACE inhibitors/ARBs and diuretics during acute illness with volume depletion risk 1
• Expect 3-4 antihypertensive medications will be needed to achieve target BP 1

Anemia Management

Evaluation and Treatment

• If anemia present (Hgb <12 g/dL women, <13 g/dL men), evaluate and treat iron deficiency first 1, 2
• If anemia persists despite appropriate iron therapy, initiate erythropoietin or analogue 1, 2
• Monitor blood pressure with each erythropoietin dose as hypertension is a common side effect 1

Mineral and Bone Disorder Management

Phosphorus Control

• If serum phosphorus >4.5 mg/dL or iPTH >100 pg/mL, implement low phosphorus diet (800-1000 mg/day) 1, 2
• Start phosphate binders if phosphorus remains >4.5 mg/dL despite dietary restriction 1, 2

Vitamin D Management

• If iPTH >100 pg/mL (or 1.5 times upper limit of normal), measure 25(OH) vitamin D 1, 2
• If 25(OH) vitamin D <30 ng/mL, give vitamin D2 50,000 units orally monthly for 6 months 1, 2

Calcium Management

• If corrected serum calcium <8.5 mg/dL (after addressing phosphorus), provide elemental calcium 1 g/day between meals or at bedtime 1, 2

Metabolic Acidosis Management

• Correct chronic metabolic acidosis to maintain serum bicarbonate ≥22 mmol/L 1, 2
• This helps slow CKD progression and prevent bone disease 1

Lipid Management

Treatment Targets

• Target LDL <100 mg/dL 1, 2
• Target non-HDL cholesterol <130 mg/dL 1
• Treat fasting triglycerides ≥500 mg/dL 1
• Evaluate for secondary causes of dyslipidemia including comorbid conditions and medications 1

Medication Management

Critical Drug Adjustments

• Discontinue metformin immediately as it is contraindicated when eGFR <30 mL/min/1.73 m² due to lactic acidosis risk 3, 4
• Avoid all NSAIDs as they are nephrotoxic 4, 2
• Adjust doses of all renally excreted medications based on GFR 2, 4
• Review all medications for nephrotoxic potential 2, 4

Contrast Imaging Precautions

• Discontinue metformin (if still taking) at time of iodinated contrast imaging procedures 3
• Re-evaluate eGFR 48 hours after imaging; restart only if renal function stable 3
• Consider alternative imaging modalities when possible 2

Lifestyle Modifications

Physical Activity

• Counsel and encourage increased physical activity if patient does not engage in regular exercise 1
• Refer to physical therapy or cardiac rehabilitation if unable to walk or increase fully mobile physical activity 1

Employment and Quality of Life

• Encourage maintaining employment and refer to vocational counseling per patient preference 1
• Provide structured education regarding preparation for RRT 1

Vaccination Requirements

• Administer pneumococcal vaccine 1
• Ensure annual influenza vaccine for patient and household contacts 1
• Provide herpes zoster vaccination (Shingrix) 1

Common Pitfalls to Avoid

• Failing to refer to nephrology when GFR <30 mL/min/1.73 m² - this is a critical error that delays preparation for RRT 1, 2
• Continuing full-dose renally excreted medications without adjustment leads to toxicity 2, 4
• Not discontinuing metformin risks fatal lactic acidosis 3
• Using iodinated contrast without precautions can precipitate acute kidney injury 3
• Neglecting to monitor and treat anemia, acidosis, and bone mineral disorders worsens outcomes 1, 2
• Delaying RRT discussions until GFR <15 mL/min/1.73 m² results in inadequate preparation and worse outcomes 1
• Placing IV lines or drawing blood from non-dominant arm veins in potential hemodialysis patients destroys future vascular access sites 1

When to Initiate Renal Replacement Therapy

• No specific GFR threshold alone mandates RRT initiation 1
• Consider initiating RRT if GFR <20 mL/min/1.73 m² with evidence of malnutrition unresponsive to nutritional intervention 1, 2
• Initiate when symptoms/signs of kidney failure develop: serositis, refractory electrolyte/acid-base abnormalities, pruritus, uncontrolled volume status or blood pressure, progressive malnutrition despite intervention, or cognitive impairment 1