Telmisartan improves vascular function independently of metabolic and antihypertensive effects in hypertensive subjects with impaired glucose tolerance

BackgroundHypertensive patients with IGT have increased risk for cardiovascular disease and progression to diabetes mellitus. Clinical trials suggest that the ARB telmisartan uniquely possesses PPARγ agonistic properties and improves insulin resistance as well as vascular endothelial dysfunction. The aim of the present study was to compare vascular effects of telmisartan and losartan in relation to their metabolic and antihypertensive effects in hypertensive patients with IGT.Materials and methods24 patients were randomised in a double-blind, prospective, cross-over trial. At baseline and after 12 weeks of either treatment an oGTT, and endothelial function testing was performed.ResultsEndothelial function improved significantly by telmisartan treatment but not by losartan treatment (FMD; T: 7.9 ± 0.7%, vs B: 6.4 ± 0.8, p < 0.01; vs L: 6.4 ± 0.6, p < 0.001) at almost identical antihypertensive effect of both agents.Insulin resistance assessed by HOMA (T: 2.20 ± 0.47 vs B: 3.04 ± 0.60, p < 0.01; vs L: 3.38 ± 0.84, T vs L p < 0.05) and ISI120 (T: 0.114 ± 0.003 vs B: 0.092 ± 0.002, p < 0.001; vs L: 0.090 ± 0.006, T vs L p < 0.01) improved significantly after telmisartan only, as did glucose tolerance (p < 0.01).The improvement of the endothelial function observed, significantly depended on pretreatment insulin resistance but was independent of improvements of insulin resistance, blood pressure or glucose tolerance.ConclusionIn hypertensive patients with IGT telmisartan compared to losartan improved endothelial function and insulin resistance independently, supporting the hypothesis that glucometabolic and vascular insulin resistance are differentially regulated.