- Willa Hsueh: Department of Medicine, Methodist Hospital Research Institute, Houston, TX 77030, USA. wahsueh@tmhs.org
Angiotensin receptor blockers (ARBs) are antihypertensive agents associated with reduced risk of new-onset diabetes mellitus. The ARB telmisartan is a partial agonist of peroxisome proliferator-activated receptor-gamma (PPAR-γ). This study evaluated the effect of telmisartan on insulin resistance, a known target of PPAR-γ agonism. Overweight/obese persons with body mass index ≥28 kg/m2, waist circumference≥35 inches, and components of the metabolic syndrome without hypertension or diabetes who were not preselected for insulin resistance were enrolled. Patients were randomized to telmisartan or matching placebo for 16 weeks. The primary efficacy measure was changed from baseline in the insulin sensitivity index (SI), calculated from oral glucose tolerance testing. SI was also evaluated in a subset of patients using a hyperinsulinemic euglycemic clamp. Secondary end points included measures of insulin sensitivity and glucose and lipid metabolism. A total of 138 patients were randomized and received ≥1 dose of study medication; 128 completed the study. At end point, no significant difference was found between telmisartan and placebo groups regarding change from baseline in SI or in glucose area under the curve. No significant between-group differences were found regarding glucose metabolism or lipoprotein levels. In the population with abdominal obesity and components of the metabolic syndrome, telmisartan did not increase insulin sensitivity.