Case Presentation

J.K., a 70-year-old woman with type 2 diabetes, is evaluated in an outpatient endocrinology clinic during a routine appointment. She was diagnosed with diabetes 5 years ago and participated in a comprehensive basic diabetes education program approximately 2 years ago.

She regularly checks her blood glucose before breakfast and 2 hours after meals. Fasting blood glucose levels typically range from 105 to 115 mg/dl, whereas postprandial blood glucose levels range from 120 to 160 mg/dl.

J.K. has no known macrovascular or microvascular complications. Her last dilated eye exam was 6 months ago. Additional medical problems include hypertension and asthma.

A review of systems was unremarkable except complaints of mild fatigue and muscle cramps.

J.K.’s current medications include:

• metformin, 500 mg once daily

• lisinopril, 5 mg once daily

• montelukast sodium, 10 mg once daily

• aspirin, 81 mg once daily

A limited physical examination revealed:

• weight: 135 lb

• height: 63 inches

• blood pressure: 110/78 mmHg

• pulse: 64

• skin: dry without rash or jaundice

• neck: thyroid 35 g

• heart: regular sinus rhythm without murmur, lungs clear to auscultation and palpation

• abdomen: soft without tenderness, mass, or bruit

• lower extremities: no edema, Homan’s negative, pedal pulses 3+ bilaterally, Carville normal

J.K.’s laboratory results were as follows:

• hemoglobin A_1c: 6.4% (normal: 4.0–6.3%)

• blood glucose: 148 mg/dl (normal: 65–110 mg/dl)

• blood urea nitrogen: 15 mg/dl (normal: 5–29 mg/dl)

• creatinine: 1.1 mg/dl (normal: 0.5–1.4 mg/dl)

• thyroid-stimulating hormone (TSH): 6.0 IU/ml (normal: 0.29–5.11 IU/ml)

• repeat TSH: 7.1 IU/ml

• thyroxine (T₄): 9.5 mg/dl (normal: 4.5–12.5 mg/dl)

• free T₄: 1.6 mg/dl (normal: 0.9–1.9 mg/dl)

• antimicrosomal antibody: 38.4 IU/ml (normal: 0–35 IU/ml)

• antithyroglobulin antibody: <20 IU/ml (normal: 0–35 IU/ml)

• total cholesterol: 211 mg/dl (normal: 130–200 mg/dl)

• triglyceride: 174 mg/dl (normal: 35–160 mg/dl)

• HDL cholesterol: 51 mg/dl (normal: 30–80 mg/dl)

• LDL cholesterol: 148 mg/dl (normal: <100 mg/dl) …