GFR CKD-EPI of 37: Stage 3b Chronic Kidney Disease
A GFR of 37 mL/min/1.73 m² indicates Stage 3b chronic kidney disease (CKD), which represents moderate-to-severe reduction in kidney function and requires immediate attention to medication dosing, cardiovascular risk management, and preparation for potential progression to kidney failure. 1
CKD Classification and Staging
Your GFR of 37 places you in Stage 3b CKD (GFR 30-44 mL/min/1.73 m²), which is distinct from Stage 3a (GFR 45-59) due to significantly higher risks of mortality and progression to kidney failure 1
The CKD-EPI equation is the recommended method for estimating GFR in adults and is more accurate than older equations, particularly at higher GFR levels 1
Stage 3b CKD carries a 3.5-fold increased risk of death compared to normal kidney function, along with elevated risks of cardiovascular disease, heart failure, stroke, and progression to dialysis 1, 2
Immediate Management Priorities
Medication Dose Adjustments
Drug accumulation due to reduced renal excretion is the most important cause of adverse drug reactions at this GFR level 1:
All renally-cleared medications must be dose-adjusted based on your GFR of 37 1
Metformin should be reviewed and dose-reduced proportionally to GFR; consider discontinuation if GFR falls below 30 1
Avoid nephrotoxic medications including NSAIDs, which pose significant risk at this level of kidney function 1
For drugs with narrow therapeutic windows (digoxin, lithium), consider measuring GFR directly or using cystatin C-based equations for more precise dosing 1
Cardiovascular Risk Management
Blood pressure control is critical: Target <130/80 mmHg, particularly if you have proteinuria 1
ACE inhibitors or ARBs should be used at maximally tolerated doses (not low doses) to slow CKD progression, even if serum creatinine increases up to 30% 1
Monitor serum potassium periodically when on ACE inhibitors, ARBs, or mineralocorticoid receptor antagonists 1
Evaluate and control dyslipidemia as cardiovascular disease risk is substantially elevated at this GFR 1
Monitoring and Surveillance
Monitor both GFR and albuminuria annually to track progression and adjust treatment 1
Check serum potassium, calcium, phosphorus, parathyroid hormone, and hemoglobin to identify CKD complications 1
Reducing albuminuria by >30% from baseline is associated with improved kidney and cardiovascular outcomes 1
Preparation for Potential Progression
You are approaching Stage 4 CKD (GFR <30), at which point you should receive education about kidney failure treatment options including transplantation, peritoneal dialysis, hemodialysis, and conservative management 3
Dialysis is typically considered when GFR falls below 15 (Stage 5), though the decision should be based on clinical symptoms (uremic complications, fluid overload, electrolyte abnormalities) rather than GFR alone 3
Timely nephrology referral is recommended for patients with Stage 3b CKD to optimize management and prepare for potential progression 1
Important Caveats
The CKD-EPI equation may misclassify kidney disease in patients with unusual muscle mass (very muscular or malnourished individuals); in such cases, cystatin C-based equations or direct GFR measurement should be considered 1
Older adults may be reclassified to more advanced CKD stages when using CKD-EPI compared to older equations, while younger patients may be reclassified to less advanced stages 4, 5
"Sick-day rules" apply: Temporarily discontinue ACE inhibitors, ARBs, diuretics, NSAIDs, metformin, and digoxin during acute illnesses that increase risk of acute kidney injury 1
Small increases in serum creatinine (up to 30%) with ACE inhibitors or ARBs should not be confused with acute kidney injury and are not a reason to discontinue these protective medications 1