Comparative effects of telmisartan and valsartan on insulin resistance in hypertensive patients with metabolic syndrome.

Objective Metabolic syndrome (MetS) is a cluster of metabolic abnormalities that includes hyperglycemia, dyslipidemia, hypertension and increased waist circumference. Individuals with this syndrome are at increased risk for development of cardiovascular disease. Since an insulin-resistance state has a critical role in the development of MetS, there is growing concern about insulin-sensitizing effects of antihypertensives, including angiotensin II receptor blockers (ARBs). Telmisartan has been reported to have an effect on the activity of peroxysome proliferator-activated receptorγ, a well-known target for insulin-sensitizing antidiabetic drugs. The aim of this study was to determine the effects of administration of two different ARBs at low doses (telmisartan at 20 mg/day and valsartan at 40 mg/day) on insulin sensitivity. Methods Patients with MetS meeting the Japanese criteria were treated with telmisartan or valsartan for 4 weeks in combination with lifestyle modification. Results A significant reduction in blood pressure was found after 4 weeks of both treatments. The homeostasis model assessment of insulin resistance (HOMA-R) was significantly reduced by telmisartan compared to the baseline value (3.11±2.06 vs 2.56±1.48, p=0.031) but was not significantly changed by valsartan. A statistically significant correlation was found between HOMA-R at baseline and changes in HOMA-R after 4 weeks of treatment only in telmisartan-treated subjects. Body mass index, glycosylated hemoglobin and lipid profile were not changed by either treatment. Conclusion Our data revealed that treatment with telmisartan even at a low dose improves insulin sensitivity in hypertensive patients with MetS. This ameliorating effect of telmisartan on glucose metabolism clinically deserves to be considered.