Free nephrology board questions: Diabetic Nephropathy

A 68-year-old man with CKD G3b, type 2 diabetes, and hypertension feels well. He exercises 4 days per week and follows a sodium-restricted diet. Medications are chlorthalidone, olmesartan, dapagliflozin, and metformin. BP is 114/62 mm Hg, and BMI is 24 kg/m². Labs (4 months ago→today): Hb 13.9→13.4 g/dL; K 4.7→5.1 mEq/L; BUN 37→38 mg/dL; creatinine 1.8→2.0 mg/dL; albumin 3.9→4.0 g/dL; HbA1c 6.8%→6.7%; urine albumin-to-creatinine ratio 24→168 mg/g. What is the next best step in management?

A 54-year-old man with type 2 diabetes, hypertension, and CKD stage 3b has 3 months of morning palpitations and diaphoresis that improve after breakfast, with glucose readings of 40–50 mg/dL. His insulin regimen and diet have not changed in 2 years. He takes insulin glargine and canagliflozin and has excellent injection technique. One year ago vs today: creatinine 2.5 vs 3.5 mg/dL; fasting glucose 118 vs 123 mg/dL; urine ACR 365 vs 500 mg/g; HbA1c 7.6% vs 6.2%. Electrolytes and BUN are normal and stable. What is the most likely cause of his morning hypoglycemia?

A 58-year-old woman with CKD stage 3, type 2 diabetes mellitus, hypertension, and hyperlipidemia presents to the outpatient clinic for routine follow-up. She feels well and has no complaints. Current medications include atorvastatin, hydrochlorothiazide, maximum dose lisinopril, and metformin. On exam, BP is 130/78 mm Hg and heart rate is 72/min. Weight is 75 kg, and body mass index is 34 kg/m². She has trace lower extremity edema. The remainder of her examination is unremarkable. Laboratory data: sodium 137 mEq/L (reference 136–145); potassium 5.2 mEq/L (3.5–5.0); chloride 102 mEq/L (98–106); CO₂ 24 mEq/L (23–28); BUN 35 mg/dL (8–20); creatinine 1.4 mg/dL (0.5–1.1); glucose 153 mg/dL (70–99, fasting); eGFR 46 mL/min/1.73 m² (≥60); hemoglobin A1c 7.9% (4.0–5.6); urine protein-to-creatinine ratio 1.9 mg/mg (<0.2). Which of the following is the MOST APPROPRIATE medication to preserve kidney function?