In a 69‑year‑old man with an estimated glomerular filtration rate (eGFR) of 66 mL/min/1.73 m², what does this indicate and how should it be managed?

Management of eGFR 66 mL/min/1.73 m²

An eGFR of 66 mL/min/1.73 m² indicates CKD Stage 2 (mildly decreased kidney function with evidence of kidney damage) and requires annual monitoring with serum creatinine, eGFR calculation, and urine albumin-to-creatinine ratio (UACR) assessment. 1

Disease Classification and Significance

• This eGFR level falls into CKD stage 2 (60-89 mL/min/1.73 m²), representing mildly decreased GFR that requires evidence of kidney damage (such as albuminuria, hematuria, or structural abnormalities) to confirm CKD diagnosis. 1
• At this level of kidney function, the patient retains approximately 66% of normal renal capacity and is at low risk for immediate complications. 1
• Important caveat: An eGFR >60 mL/min/1.73 m² does not exclude kidney disease, as normal values overlap with early CKD stages. 2

Confirmation of Chronicity

• Repeat eGFR measurement within 3 months to verify chronicity, as CKD requires persistent abnormalities for ≥3 months. 3
• Do not rely on serum creatinine concentration alone; always calculate eGFR using validated equations (CKD-EPI equation is preferred over MDRD). 3, 4
• If creatinine-based eGFR appears discordant with clinical picture, consider measuring cystatin C-based eGFR for confirmation, as creatinine estimates can be inaccurate in 16-20% of individuals. 5

Mandatory Annual Monitoring

• Kidney function: Measure serum creatinine and calculate eGFR annually. 1
• Albuminuria: Obtain annual quantitative UACR to detect progressive kidney damage. 1
• Blood pressure: Check at every clinical visit, targeting <130/80 mmHg. 1
• Increase monitoring frequency to every 6 months if eGFR shows progressive decline (>5 mL/min/1.73 m² per year) or if diabetes is present. 1

Medication Management

• No dose adjustments required: At eGFR 66 mL/min/1.73 m², most medications can be used at standard doses. 1
• Fenofibrate: Can be used at normal doses (reduction only required when eGFR <60 mL/min/1.73 m²). 1
• ACE inhibitors or ARBs: Use at standard doses if hypertension and/or albuminuria are present, with appropriate monitoring of serum creatinine and potassium after initiation. 1
• Avoid nephrotoxins: Minimize prolonged NSAID use, as these agents reduce renal blood flow and can precipitate acute kidney injury. 1

Prevention of CKD Progression

• Optimize glycemic control if diabetes is present, targeting HbA1c ≈7% to delay CKD progression. 1
• Blood pressure control with ACE inhibitors or ARBs as first-line agents if hypertension and albuminuria coexist. 1
• Address cardiovascular risk factors: Smoking cessation, weight management, and regular physical activity. 1
• Dietary considerations: No protein restriction is needed at this eGFR level (restriction to 0.8 g/kg/day only applies when eGFR <45 mL/min/1.73 m²). 5

Nephrology Referral Criteria

• Consider nephrology referral if any of the following develop: 1
  • Rapid eGFR decline (>5 mL/min/1.73 m² per year)
  • Significant proteinuria (UACR >300 mg/g)
  • Difficult-to-control hypertension despite multiple agents
  • Suspected non-diabetic kidney disease (hematuria, rapid progression, systemic symptoms)
• Mandatory referral is not required at this eGFR level; referral becomes mandatory when eGFR falls below 30 mL/min/1.73 m². 3

Escalation of Care

• If eGFR declines to <60 mL/min/1.73 m² (Stage 3a), increase monitoring frequency and begin screening for CKD complications including anemia, mineral-bone disorder, metabolic acidosis, and electrolyte abnormalities. 1
• At eGFR <45 mL/min/1.73 m² (Stage 3b), nephrology referral becomes appropriate even without other high-risk features. 5

Common Pitfalls to Avoid

• Do not assume normal kidney function: Even though eGFR is >60 mL/min/1.73 m², the presence of albuminuria or other markers indicates established kidney disease requiring ongoing surveillance. 2
• Do not overlook cardiovascular risk: CKD at any stage increases cardiovascular disease risk and warrants aggressive risk factor modification. 1
• Do not use creatinine alone: Always calculate and report eGFR rather than relying on serum creatinine concentration, which can be misleading in patients with altered muscle mass. 3