Staging

• eGFR: about 26 mL/min/1.73 m² by CKD-EPI 2021 (my calculation for a 60-year-old male). This is G4, severely decreased.
• Albuminuria: more than 300 mg/g is A3, severely increased.
• Overall: G4A3 is the KDIGO "very high risk" category. It carries a high risk of progression to kidney failure and of cardiovascular events.
• Chronicity: you need to confirm this has lasted more than 3 months. If it hasn't, rule out acute kidney injury (AKI) on top of CKD.

What to confirm first

1. Is it diabetic kidney disease? It is likely if there is a long duration of diabetes and retinopathy. Absent retinopathy, rapid GFR decline, active urinary sediment (RBC casts), or nephrotic-range proteinuria with a short diabetes history should prompt a search for another cause. Consider nephrology review and possibly a biopsy.
2. Basic tests:
   • Repeat creatinine, eGFR and UACR.
   • Urine routine and microscopy, and a 24-hour urine protein or PCR.
   • Electrolytes (especially potassium), bicarbonate, calcium, phosphate, PTH, vitamin D, and hemoglobin and iron studies.
   • HbA1c, lipid profile, and uric acid.
3. Imaging: renal ultrasound for kidney size, cortical thickness and obstruction. Small kidneys suggest chronicity. If the kidneys are asymmetric, think of renal artery stenosis in a long-standing hypertensive.
4. Other tests: fundus exam for retinopathy, and an ECG and echo, since cardiovascular risk is high.
5. Rule out secondary causes if there are clues: hepatitis B and C, HIV, serum and urine protein electrophoresis (SPEP/UPEP) with free light chains, and complement and ANA if indicated.

Management

1. RAAS blockade
   • Start an ACEi or ARB at a low dose and titrate to the maximum tolerated dose.
   • Check creatinine and potassium 1 to 2 weeks after starting or changing the dose.
   • A creatinine rise of up to 30% is acceptable. Stop and investigate if it rises more than that, or if potassium goes above about 5.5 mmol/L.
2. SGLT2 inhibitor (dapagliflozin 10 mg or empagliflozin 10 mg)
   • It slows CKD progression and reduces heart failure and cardiovascular events.
   • It can be started at eGFR 20 or above and continued even if eGFR later falls. Its glucose-lowering effect is weak at this eGFR, but the kidney and heart benefit remains.
   • Counsel on genital infections and on sick-day rules (hold it during vomiting, diarrhea or poor intake). Expect a small early eGFR dip.
3. Finerenone (nonsteroidal mineralocorticoid receptor antagonist)
   • Add it if albuminuria persists despite the maximum tolerated ACEi or ARB, potassium is 4.8 mmol/L or below, and eGFR is 25 or above.
   • He is borderline at eGFR about 26.
   • Monitor potassium closely.
4. Blood pressure
   • The KDIGO 2021 target is systolic below 120 mmHg with standardized measurement, if tolerated. A target of about 130/80 is more practical.
   • Add amlodipine and/or a diuretic as needed. At eGFR below 30, a loop diuretic works better than a thiazide.
   • Restrict sodium to less than 2 g/day.
5. Glycemia
   • Aim for an individualized HbA1c, often 7 to 8%, because hypoglycemia risk rises as GFR falls.
   • Metformin: stop it if eGFR is below 30.
   • Sulfonylureas: avoid long-acting ones such as glibenclamide.
   • Insulin: requirements often fall, so watch for hypoglycemia.
   • DPP-4 inhibitors: linagliptin needs no renal dose adjustment. Other DPP-4 inhibitors do.
   • GLP-1 receptor agonist: consider one for cardiovascular and kidney benefit.
6. Cardiovascular risk
   • Start a statin (atorvastatin, or add ezetimibe).
   • Use aspirin only if he has established atherosclerotic disease.
   • Stop smoking, and exercise and manage weight.
   • Protein intake of about 0.8 g/kg/day.
7. Avoid nephrotoxins: NSAIDs, contrast without precautions, and aminoglycosides. Adjust renal dosing for all drugs.
8. CKD complications
   • Treat anemia (iron first, then an erythropoiesis-stimulating agent if hemoglobin is below 10).
   • Correct metabolic acidosis (sodium bicarbonate if serum bicarbonate is below 22).
   • Manage hyperkalemia, and phosphate and PTH abnormalities.
   • Vaccinate against hepatitis B, pneumococcus and influenza.
9. Referral and follow-up
   • Refer to nephrology now. At G4 this is indicated for CKD education, preparing for kidney replacement therapy, and vascular access planning.
   • A 5-year kidney failure risk above about 3 to 5% (Kidney Failure Risk Equation, KFRE) is also a referral trigger.
   • Follow up every 1 to 3 months.
   • Preserve the non-dominant arm veins and avoid PICC lines.

Recent evidence check

• PMID 42212277
• PMID 40213686
• PMID 39758344

What this changes

• Sub-nephrotic albuminuria with long-standing diabetes and hypertension fits diabetic kidney disease and hypertensive nephrosclerosis.
• You don't need a biopsy-level workup for the proteinuria alone. Look for another cause only if there is no retinopathy, the diabetes is of short duration, the sediment is active, or GFR is falling fast.
• Check the 24-hour collection is complete. Urinary creatinine should be about 15 to 20 mg/kg/day in men. A urine albumin-creatinine ratio (UACR) on a spot sample gives a second check.

• Osmotic diuresis from hyperglycemia. Check blood glucose and HbA1c, and look for glycosuria.
• Loss of concentrating ability from CKD. This is common at G4 and causes isosthenuria and nocturia. Check urine osmolality and specific gravity.
• Diuretic use. Loop diuretics are often used for hypertension at this eGFR. An SGLT2 inhibitor also adds to urine volume.
• Obstructive uropathy. In a 60-year-old male, BPH or bladder outlet obstruction can cause high-output obstruction. Do a renal ultrasound with a post-void residual, and ask about voiding symptoms.
• Electrolyte causes. Check for hypercalcemia and hypokalemia.
• Diabetes insipidus. This is unlikely. Consider it only if urine osmolality is persistently low with normal glucose and calcium.
• Fluid intake. Ask about habitual high intake.

• Don't restrict fluids. With a 3 L output and a GFR of 26, he is prone to volume depletion.
• Volume depletion can cause pre-renal AKI on top of CKD, especially with an ACEi or ARB, an SGLT2 inhibitor, or a diuretic.
• Check orthostatic blood pressure, weight and edema.
• Teach sick-day rules: hold the ACEi or ARB, SGLT2 inhibitor, diuretic and metformin during vomiting, diarrhea, fever or poor intake.
• Check sodium, potassium and bicarbonate. Polyuria with a tubular defect can cause hypokalemia, hyperkalemia or acidosis.

Treatment priorities

1. Start or optimize the ACEi or ARB with a creatinine and potassium check after 1 to 2 weeks.
2. Add an SGLT2 inhibitor, which is allowed down to eGFR 20. Start it only once he is euvolemic, and reduce or stop the diuretic if needed.
3. Consider finerenone if albuminuria persists and potassium is 4.8 mmol/L or below. His eGFR of about 26 is borderline for starting.
4. Keep blood pressure at or below about 130/80, or systolic below 120 if tolerated. Restrict sodium, but not at the cost of volume depletion.
5. Stop metformin at eGFR below 30. Prefer linagliptin, insulin, or a GLP-1 receptor agonist.
6. Start a statin, and avoid NSAIDs and contrast.
7. Refer to nephrology now, given G4A3.

Report as I read it (Rama Rao, scan dated 12/10/26)

What it means for his kidney disease

• Normal adult kidney length is about 10 to 12 cm. Both of his are small, at 8.7 cm and 8 cm.
• Grade 2 changes mean increased cortical echogenicity, which indicates chronic medical renal disease.
• Together with the eGFR of about 26, this supports established, mostly irreversible CKD.
• Early diabetic nephropathy usually has normal or enlarged kidneys. Small kidneys here mean he is in the late stage.

• A kidney biopsy is not advisable. Small shrunken kidneys carry a higher bleeding risk and low diagnostic yield.
• A reversible cause such as a large renal mass or obstruction is less likely, but the report doesn't comment on hydronephrosis or calculi. Ask the radiologist to confirm there is no hydronephrosis or hydroureter, and ask for cortical thickness.
• The two kidneys are similar in size, and the 0.7 cm difference is under the roughly 1.5 cm that would raise concern for renal artery stenosis.

• The bladder was near empty and the prostate window was poor, so you can't exclude outflow obstruction.
• That matters because of the 3 L/day urine output, which can be a high-output obstructive pattern.
• Repeat with a full bladder and a post-void residual (PVR). Check PSA and do a digital rectal exam. Ask about weak stream, hesitancy and nocturia.

• Examine for reducibility and signs of obstruction or strangulation. Refer to surgery.
• Chronic straining from prostatic obstruction or constipation can worsen it.
• If he later needs peritoneal dialysis, a hernia should be repaired first, since it raises intra-abdominal pressure and leak risk.
• Check renal dosing and anesthetic risk before any elective repair.

• This is common with diabetes and metabolic syndrome.
• Check liver enzymes and calculate FIB-4 to assess fibrosis risk.
• A statin is safe and still indicated.
• A GLP-1 receptor agonist helps both the liver and the kidney, and weight loss and exercise help.
• Avoid pioglitazone, which causes fluid retention.

Where this leaves the plan