Case Studies

Metformin Fails in T2DM Patient

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A 55-year old Caucasian woman has been under your care for three years. Eighteen months ago you diagnosed her with type 2 diabetes mellitus (T2DM). She has a history of mild hypertension, hypercholesteremia, and retinopathy.


A 55-year old Caucasian woman has been under your care for three years. Eighteen months ago you diagnosed her with type 2 diabetes mellitus (T2DM). She has a history of mild hypertension, hypercholesteremia, and retinopathy.

However, she has no history of microalbuminuria, neuropathy, or cardiovascular events and reports no cardiac symptoms.  

When you diagnosed her with T2DM, you initiated her on metformin (500 mg b.i.d.) and, because she was obese, advised her to lose weight through specific dietary changes and a commitment to a regular walking program of 30 minutes per day. Since then you have seen her twice (every six months) and have increased her dosage each time because her HbA1c has remained above 7.0%. During these subsequent visits she reported intermittent success with modest weight loss, losing 10-15 pounds but repeatedly regaining it. For the past six months, she has been on a maximally effective dose of metformin (1,000 mg b.i.d.). Additionally, she is taking hydrochlorothiazide (25 mg daily) and lisinopril (20 mg daily) for her hypertension, simvastatin (20 mg daily) for her hypercholestermia, and aspirin (81 mg daily) for cardioprotection. She reports taking these medications consistently. 
 
The patient’s HbA1c is 7.6%, which is an increase from 7.2% six months ago, and her fasting blood glucose level was 163 mg/dl and ranges between 150 and 170 mg/dl. Her LDL, HDL, and triglycerides are in target range. Additional lab tests show normal results for thyroid, renal, and liver function. 
 
Your recent physical examination shows normal cardiorespiratory, abdominal, and neurologic findings. With medications, her blood pressure measured 128/78 mmHg. A recent ophthalmic exam confirmed mild, non-proliferative retinopathy.
 
Presently her BMI (body-mass index) is 31 kg/m2. She reports only being able to walk occasionally during the week due to work and family obligations but says she walks most weekends when the weather is good.
 
The patient has health insurance through her employer, which includes prescription drug coverage. She is seeking advice about the management of her diabetes.  
 
Treatment Options 
 
Which one of the following treatment options do you think would be most appropriate for this patient? 
 
1.  Add a sulfonylurea (SU)
2. Add a thiazolidinedione (TZD)
3. Add an incretin therapy (GLP-1 agonist or DPP-4 inhibitor)

Management options

1. Sulfonylurea (SU)

Charles McClave, MD
General Internist

2. Thiazolidinedione (TZD)

David M. Kendall, MD
Endocrinologist

3. Glucagon-like peptide 1 (GLP-1)

David A. D'Alessio, MD
Endocrinologist