64-year female presents to your office for her 3-month follow-up. She has previously been diagnosed with mild diastolic heart failure, secondary to hypertension. She currently takes an ace-inhibitor and a diuretic with good control of her heart failure symptoms and hypertension. At her last visit, she had a FPG 118 mg/dl. In a subsequent conversation with her, you discussed how she has developed prediabetes and suggested lifestyle modifications. Since her last visit, she has taken up very gentle walking four times/week and has changed her diet to a more healthful one. Despite these positive changes, this visit's labs return an A1C 7.8%; her remaining labs are within normal limits. Which one of the following antihyperglycemic medication classes would you choose to initiate treatment?
Answer: B. Biguanides
Metformin would be considered the first-line drug of choice for this patient. The use of metformin in patients with diabetes and heart failure used to be contraindicated (its use in patients with compromised renal function being associated with lactic acidosis). However, it can now be used in select patients with heart failure if renal function is normal, CV status is stable and ventricular dysfunction is not severe. Eurich, et al. (2005) conducted a retrospective analysis of type 2 diabetes patients treated with metformin vs. sulfonylureas and found overall decreased mortality in the metformin group. Masoudi et al (2005) examined metformin vs. thiazolidinediones and found the reduced risk of death at 1-year and lower hospital admission rates in the metformin group, while increased hospital admissions (primarily due to heart failure readmissions) was seen in the thiazolidinedione group. Thiazolidinediones increase renal sodium and water reabsorption, causing fluid retention and worsening of heart failure signs/symptoms. A recent retrospective analysis (Tzoulaki, et al., 2009) found an association between the use of sulfonylureas and increased risk of developing/worsening heart failure. Both classes of drugs should not be used in patients with diabetes and heart failure.
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