Management of CKD Stage 3a (GFR 36 mL/min/1.73 m²)
For a patient with CKD stage 3a and GFR 36 mL/min/1.73 m², immediately initiate comprehensive nephroprotective therapy including blood pressure optimization, assess albuminuria status to guide medication selection, and establish regular monitoring to prevent progression to stage 4 disease. 1
Initial Diagnostic Assessment
Measure spot urine albumin-to-creatinine ratio (ACR) immediately if not already done, as albuminuria status fundamentally changes risk stratification and treatment intensity. 2, 3 A GFR of 36 mL/min/1.73 m² places this patient at the lower end of stage 3a (45-59 mL/min/1.73 m²), approaching stage 3b (30-44 mL/min/1.73 m²). 1, 3
Confirm the diagnosis by verifying that abnormal kidney function has persisted for at least 3 months with two separate eGFR measurements 91-730 days apart. 4, 5 This distinguishes chronic from acute kidney disease. 3
Obtain baseline serum potassium, creatinine, complete metabolic panel, hemoglobin, phosphate, parathyroid hormone (PTH), and vitamin D levels. 4 At GFR <60 mL/min/1.73 m², complications including anemia, metabolic acidosis, hyperphosphatemia, and secondary hyperparathyroidism become increasingly prevalent. 1, 4
Calculate the rate of eGFR decline over the past 1-2 years if prior measurements are available. 5, 6 A decline >3 mL/min/1.73 m²/year indicates rapid progression and warrants more aggressive intervention and earlier nephrology referral. 5, 6
Blood Pressure Management
Target systolic blood pressure <130 mmHg (but not <120 mmHg) for all patients with CKD and hypertension. 2 This target is supported by strong evidence from the SPRINT trial. 2
If ACR ≥30 mg/g, start an ACE inhibitor or ARB immediately as first-line therapy, even if blood pressure is at target, because these agents provide blood pressure-independent nephroprotection. 7, 2 The 2023 Diabetes Care guidelines strongly recommend this approach. 7
If ACR <30 mg/g, an ACE inhibitor or ARB may still be used for hypertension control, though the nephroprotective indication is less robust. 7, 2
Recheck serum creatinine and potassium 2-4 weeks after initiating or uptitrating an ACE inhibitor/ARB. 7, 2 Continue the medication unless serum creatinine rises >30% within 4 weeks; smaller rises represent expected hemodynamic changes and do not require discontinuation. 7, 2
Manage hyperkalemia with dietary modification or potassium binders rather than discontinuing the RAS blocker whenever possible. 2 Stopping these medications eliminates critical nephroprotection. 2
Nephroprotective Medication Strategy
If ACR ≥200 mg/g (≥20 mg/mmol):
Start an SGLT2 inhibitor (empagliflozin, canagliflozin, or dapagliflozin) immediately, as the patient's GFR of 36 mL/min/1.73 m² exceeds the minimum threshold of ≥20 mL/min/1.73 m². 7, 2 This is a Level 1A recommendation with the strongest evidence for reducing CKD progression and cardiovascular events. 2
Continue the SGLT2 inhibitor even if eGFR subsequently falls below 20 mL/min/1.73 m², unless the drug is not tolerated or the patient initiates dialysis. 2
Expect an initial reversible eGFR decline of 2-3 mL/min/1.73 m² within the first 2 weeks; this does not require discontinuation. 2 This represents hemodynamic adjustment, not kidney injury.
Consider adding a non-steroidal mineralocorticoid receptor antagonist (finerenone) if albuminuria persists despite maximally tolerated ACE inhibitor/ARB, potassium is normal, and eGFR remains >25 mL/min/1.73 m². 7, 2
If ACR 30-199 mg/g with diabetes:
If ACR <200 mg/g without diabetes:
- Consider an SGLT2 inhibitor, as evidence supports benefit even in patients without significant albuminuria, particularly at this GFR range (36 mL/min/1.73 m²). 2 This is a 2B recommendation for eGFR 20-45 mL/min/1.73 m². 2
Cardiovascular Risk Reduction
Initiate statin therapy if not already prescribed, as the majority of CKD patients have a 10-year ASCVD risk ≥10%, placing them in the high-risk category. 2 Approximately 71% of adults with hypertension and 63.2% with hypercholesterolemia have overlapping conditions. 2
Statins do not require dose adjustment at this level of kidney function. 2
Screen for diabetes with HbA1c if not recently done, as approximately 27% of hypertensive patients have diabetes. 2
Address smoking cessation if applicable, as this is a major modifiable cardiovascular risk factor. 2
Dietary and Lifestyle Modifications
Restrict dietary protein intake to 0.8 g/kg body weight per day for non-dialysis-dependent stage 3 CKD. 7 This recommendation comes from the 2023 Diabetes Care guidelines. 7
Restrict dietary sodium to <2.0 g/day (<90 mmol/day). 7
Avoid NSAIDs entirely, especially in combination with ACE inhibitor/ARB and diuretics (the "triple whammy"), as this markedly increases acute kidney injury risk. 2, 4
Monitoring Schedule
Perform laboratory monitoring (creatinine, eGFR, ACR, potassium, hemoglobin, phosphate) every 3-6 months initially, with frequency adjusted based on clinical stability and medication regimen. 2, 3 Stage 3a CKD warrants biological control 2-4 times per year based on severity. 3
Monitor blood pressure every 6-8 weeks until target is achieved, then less frequently once stable. 2
Assess for CKD complications at each visit, including anemia (hemoglobin), bone disease (phosphate, calcium, PTH, vitamin D), metabolic acidosis (bicarbonate), and hyperkalemia. 1, 4 The prevalence of these complications rises significantly when GFR declines below 60 mL/min/1.73 m². 1
Calculate eGFR trajectory at each visit to identify rapid progressors (decline >3 mL/min/1.73 m²/year). 5, 6 Renal function trajectory is more important than CKD stage alone for predicting outcomes. 6
Nephrology Referral Criteria
Refer to nephrology now if ACR ≥300 mg/g, especially with progressive increases. 7, 2 The 2023 Diabetes Care guidelines recommend referral when eGFR is <30 mL/min/1.73 m², which this patient is approaching. 7
Refer immediately if eGFR decline is >5 mL/min/1.73 m² per year or if there is a decline in GFR category accompanied by a ≥25% drop in eGFR from baseline. 2
Refer promptly for uncertainty about the etiology of kidney disease, difficult management issues, or rapidly progressing kidney disease. 7
Consider nephrology consultation even without meeting absolute criteria, as stage 3a with complications or progression warrants specialist input. 1
Critical Pitfalls to Avoid
Never discontinue ACE inhibitor/ARB for creatinine rises <30% unless there is clear volume depletion; stopping eliminates nephroprotection. 2 A recorded CKD diagnosis is associated with significant improvements in management and attenuated eGFR decline. 5
Do not stop an SGLT2 inhibitor because of the expected initial eGFR dip of 2-3 mL/min/1.73 m². 2
Always calculate eGFR using the CKD-EPI equation rather than relying on serum creatinine alone. 2, 8, 9 The CKD-EPI equation is more accurate than the MDRD Study equation, especially at GFR levels between 30-90 mL/min/1.73 m². 9
Do not ignore albuminuria status; classify using the complete CGA system (Cause, GFR category, Albuminuria category), not GFR alone. 3 Stage 3a with normal albuminuria (A1) represents moderately high risk, while stage 3a with severe albuminuria (A3) represents high risk. 1
Patient Education
Educate on "sick-day rules": temporarily hold ACE inhibitor/ARB, diuretics, and SGLT2 inhibitors during acute illnesses with volume depletion (vomiting, diarrhea, fever). 2
Withhold SGLT2 inhibitors during prolonged fasting, surgery, or critical illness due to ketoacidosis risk. 2
Emphasize that delayed diagnosis is associated with elevated risk of CKD progression to stage 4/5 (hazard ratio 1.40 per year of delay), kidney failure (HR 1.63), and composite cardiovascular events (HR 1.08). 5 Early intervention significantly reduces annual eGFR decline from 3.20 to 0.74 mL/min/1.73 m² after diagnosis. 5