O.B. is a 67-year-old African-American man who has had type 2 diabetes for 11 years. He was diagnosed incidentally through laboratory testing. Metformin was initiated at diagnosis and eventually titrated to his current dose of 1,000 mg twice daily. Because of his A1C of 7.5%, his primary care provider started him on sitagliptin, 100 mg daily, 4 years ago. Despite dual oral therapy, his blood glucose levels are still not at goal.
He is self-referred to the clinic for help with blood glucose management. He checks his blood glucose once daily fasting. His results, by memory, are 175–190 mg/dl in the morning before breakfast.
He has seen a dietitian in the past and is trying to maintain a diet that includes carbohydrates in the amounts of 60 g for breakfast, 45 g for lunch, 15 g for a snack, and 60 g for dinner. However, he has restaurant carryout food for dinner about five times per month, consisting of pizza or barbecue items with French fries. His exercise is limited by right-knee osteoarthritis.
His medical and surgical history includes hypertension treated with lisinopril, hyperlipidemia treated with pravastatin, right-knee osteoarthritis, a right hip replacement at the age of 61 years, pneumothorax at the age of 35 years, and benign prostatic hypertrophy. He has no complications from his diabetes.
On physical exam, his height is 5′9″, weight is 210 lb, and BMI is 31 kg/m2. His blood pressure is 146/77 mmHg, and his heart rate is 83 bpm. He has no acanthosis nigricans or skin tags on the neck. Physical exam is remarkable for limited range of motion in the right knee and a scar on the right lower extremity from previous hip surgery. He has no peripheral neuropathy.
In the clinic, his random blood glucose is 254 mg/dl. On …