I have an estimated glomerular filtration rate (eGFR) of 50 mL/min/1.73 m²; what does this indicate and how should it be managed?

Management of eGFR 50 mL/min/1.73 m²

An eGFR of 50 mL/min/1.73 m² indicates Stage G3a chronic kidney disease (moderately decreased kidney function), which requires systematic screening for complications, medication adjustments, and cardiovascular risk reduction, but does not yet mandate nephrology referral unless other high-risk features are present. 1

Disease Classification and Risk Stratification

• Stage G3a CKD is defined by eGFR 45-59 mL/min/1.73 m², representing loss of approximately half of normal kidney function. 1
• This level carries increased risk for cardiovascular disease, CKD progression, and mortality compared to normal kidney function. 1
• Confirm chronicity by repeating eGFR within 3 months, as CKD requires persistent abnormalities for ≥3 months; a single measurement is insufficient. 1
• If creatinine-based eGFR appears discordant with clinical presentation (muscle wasting, extremes of body mass, or non-steady state), measure cystatin C-based eGFR, as creatinine estimates are inaccurate in 16-20% of individuals with eGFR <60 mL/min/1.73 m². 1, 2

Mandatory Screening for CKD Complications

• Screen every 6-12 months for blood pressure control, volume status, electrolyte abnormalities (potassium, sodium), metabolic acidosis (serum bicarbonate), anemia (hemoglobin), and mineral bone disease (calcium, phosphorus, PTH). 1
• Measure urine albumin-to-creatinine ratio (UACR) at least annually to assess for albuminuria. 1
• Monitor eGFR and UACR at least annually to track progression. 1

Blood Pressure and Proteinuria Management

• Target blood pressure <130/80 mmHg to reduce cardiovascular risk and slow CKD progression. 1
• If albuminuria is present (UACR ≥30 mg/g), initiate ACE inhibitor or ARB as first-line antihypertensive therapy. 1
• Monitor serum creatinine and potassium 1-2 weeks after starting or adjusting ACE inhibitor/ARB doses. 1
• Restrict sodium intake to <2 g/day (equivalent to <5 g sodium chloride) to optimize blood pressure control and reduce proteinuria. 3, 1

Medication Management

• Review all medications for dose adjustments, as many drugs require modification when eGFR <60 mL/min/1.73 m². 1
• Strictly avoid NSAIDs, as they reduce renal blood flow and can precipitate acute kidney injury even at this level of function. 1
• Metformin is safe to continue at eGFR 50 mL/min/1.73 m² but requires discontinuation if eGFR falls below 30 mL/min/1.73 m². 4

Glycemic Control (If Diabetic)

• Target HbA1c of approximately 7% to delay CKD progression, as intensive glucose control reduces albuminuria onset and slows eGFR decline. 1
• For patients with type 2 diabetes and eGFR ≥30 mL/min/1.73 m², treat with metformin and an SGLT2 inhibitor as first-line therapy. 3
• If glycemic targets are not achieved or these agents are not tolerated, add a long-acting GLP-1 receptor agonist. 3
• SGLT2 inhibitors provide substantial cardiovascular and kidney protection, reducing risks of CKD progression and cardiovascular events. 3

Dietary and Lifestyle Modifications

• Limit dietary protein to approximately 0.8 g/kg body weight per day to reduce hyperfiltration injury and slow progression. 1
• Engage in moderate-intensity physical activity for at least 150 minutes per week and avoid sedentary behavior. 3
• Restrict dietary sodium to <2 g/day as noted above. 1

Nephrology Referral Criteria

• Nephrology referral is not yet mandatory at eGFR 50 mL/min/1.73 m² unless specific high-risk features are present. 1
• Refer promptly if there is uncertainty about etiology of kidney disease, difficult management issues (refractory hypertension, electrolyte disorders), rapidly progressing kidney disease (eGFR decline >5 mL/min/1.73 m² per year), or confirmed proteinuria with UACR ≥300 mg/g. 1
• Mandatory referral becomes necessary when eGFR falls below 30 mL/min/1.73 m². 4

Vaccination

• Administer hepatitis B vaccination early if the patient is likely to progress to end-stage kidney disease, as vaccine response diminishes with declining kidney function. 1

Critical Pitfalls to Avoid

• Do not underestimate cardiovascular risk: CKD at eGFR 50 mL/min/1.73 m² substantially increases cardiovascular disease risk, requiring aggressive modification of all cardiovascular risk factors (blood pressure, lipids, diabetes control, smoking cessation). 1, 5
• Do not rely on serum creatinine alone; always calculate and report eGFR using validated equations (CKD-EPI is more accurate than MDRD at this level). 1, 2
• Do not continue NSAIDs, even for short courses, as they pose significant risk of acute-on-chronic kidney injury. 1
• A large positive difference between creatinine-based and cystatin C-based eGFR (eGFRcreat >> eGFRcys) is associated with higher cardiovascular event risk and faster coronary artery calcification progression, warranting closer cardiovascular monitoring. 6