Hypertensive patients with the cardiometabolic syndrome (CMS) are at increased risk for type 2 diabetes and cardiovascular disease. The authors examined effects of valsartan and hydrochlorothiazide (HCTZ) combined and alone on insulin sensitivity (using homeostasis model assessment-insulin resistance [HOMA-IR]), and inflammatory/metabolic biomarkers in prediabetic hypertensive persons with CMS. Eligible patients entered 16-week therapy with valsartan 320 mg/d (n=189), HCTZ 25 mg/d (n=190), or valsartan/HCTZ 320/25 mg/d (n=187). At the end point, there were no statistically significant differences in HOMA-IR among the 3 groups. HCTZ significantly increased hemoglobin A(1c) and triglyceride concentrations and lowered serum potassium levels vs valsartan. HCTZ also increased plasma aldosterone and C-reactive protein levels. Blood pressure reduction and blood pressure control rates were highest with valsartan/HCTZ. There were no differences between combination valsartan/HCTZ or monotherapies on a measure of insulin sensitivity; however, the negative metabolic effects of HCTZ (increase in triglyceride and hemoglobin A(1c) values) were absent with valsartan/HCTZ, indicating an ameliorating effect of valsartan on these measures.