A 63-year-old woman with long-standing type 2 diabetes, hypertension, osteoarthritis, and controlled systolic congestive heart failure following a previous anterior myocardial infarction presents for a routine office visit. She denies any significant complaints. The patient faithfully takes her glargine insulin, lisinopril, carvedilol, furosemide, and aspirin. On examination her blood pressure is 122/82, pulse 85, RR 14, with clear lungs, regular heartbeat, and 1+ bilateral pedal edema. You review the chart and find that her baseline creatinine is 1.5 mg/dL with an estimated glomerular filtration (GFR) rate of 42 mL/min. Her laboratory studies drawn early the morning of the visit returns as follows:Na: 138 mEq/LK: 6.0 mEq/LHCO3: 15 mEq/LCl: 120 mEq/LBUN: 20 mg/dLCreatinine: 1.8 mg/dLGlucose: 183 mg/dLYou suspect she has a Type 4 renal tubular acidosis. What is the most common pathophysiologic scenario leading to this acid-base disturbance?