Left ventricular diastolic function in patients with type 2 diabetes treated with a dipeptidyl peptidase-4 inhibitor- a pilot study

BACKGROUND Blood glucose control is fundamental albeit not enough to prevent diabetic macrovascular complications. Dipeptidyl peptidase-4 (DPP-4) inhibitors are effective in improving metabolic parameters in patients with type 2 diabetes mellitus (T2DM) but little is known about its cardiovascular effects. We compared the DPP-4 inhibitor sitagliptin with bedtime NPH insulin (NPH) as add-on therapy in patients with T2DM, aiming to ascertain which drug would have additional cardioprotective effects. METHODS Thirty-five T2DM patients inadequately controlled with metformin plus glyburide were randomized to receive sitagliptin (n = 18) or NPH (n = 17) for 24 weeks. Fasting plasma glucose, HbA1c, lipid profile, C-reactive protein, active glucagon-like peptide (aGLP-1) levels, 24-hour ambulatory blood pressure measurement and comprehensive 2-dimensional echocardiogram were determined before and after treatments. RESULTS Both sitagliptin and NPH therapies decreased HbA1c levels after 24 weeks. Fasting plasma glucose and triglyceride levels decreased in the NPH group whereas only sitagliptin increased aGLP-1 levels. Left ventricular diastolic dysfunction (LVDD) was detected in 58.6% of twenty-nine patients evaluated. Beneficial effects in LVDD were observed in 75% and 11% of patients treated with sitagliptin and NPH, respectively (p = 0.015). Neither therapy changed C-reactive protein or blood pressure. CONCLUSIONS Sitagliptin and bedtime NPH were similarly effective on glucose control. Improvement in LVDD in T2DM patients treated with sitagliptin was suggested, probably related to the increase of aGLP-1 levels. Therefore, DPP-4 inhibitor seems to have cardioprotective effects independent of glucose control and may have a role in the prevention of diabetic cardiomyopathy.