A 58-year-old woman who has had diabetes for 6 years currently takes metformin 500 mg twice daily. She strictly adheres to her diet and exercise regimen. At a routine evaluation, her blood pressure varies on several readings but remains in the range of 145–150/85–90 mm Hg. Laboratory values are a hemoglobin A1c value of 6.4%, a urine albumin–creatinine ratio of 90 to 120 mg/g on multiple measurements, and a serum creatinine level of 1.0 mg/dL (88.42 µmol/L).