A 45-year-old Black man presents to his physician for a routine exam. The patient has a history of being overweight since childhood. As of his last exam several months ago, his BMI was 33. He is experiencing polyuria, especially at nighttime, and reports being thirsty all the time. He has noticed a change in his vision in the last few months and has had to get reading glasses, but still experiences blurred vision. He also reports feeling cold a lot as well as having itchy, dry skin that lasted beyond the winter months.

Physical exam reveals increased central adiposity. His blood pressure is 160/85 mm Hg. His eyes appear bloodshot, and his skin appears dry, especially on the feet, which feel cold to the touch. His hands are also cold to the touch. There is acanthosis nigricans on the neck and axilla. His other vital signs are body temperature, 98.6 °F; respiratory rate, 17 breaths/min; heart rate, 78 beats/min; height, 5 ft 10 in; and weight, 230 lb; which is 10 lb heavier than at his last exam 3 months ago. He has a history of uncontrolled hypertension and has declined pharmacologic intervention to help control it because he was concerned about medication side effects. Heart and breath sounds are normal on auscultation, although the patient's breathing is slightly labored and his heart rate is fast. His abdomen is soft, and his liver and spleen are normal on palpation. Funduscopic exam reveals dilatation of the retinal venules in the right eye. Neurologic exam is unremarkable.