Effects of an olmesartan/amlodipine combination compared to olmesartan or amlodipine monotherapies on some insulin resistance parameters in hypertensive patients

Abstract

Purpose: To evaluate the effects of a fixed olmesartan/amlodipine combination on blood pressure control, lipid profile, and some insulin resistance parameters compared to single monotherapies. Methods: After a 2 week wash-out period, 276 hypertensive patients were randomly assigned to olmesartan 20 mg, amlodipine 10 mg or to a single pill containing a fixed dose of olmesartan/amlodipine 20/5 mg for 12 months. We evaluated at baseline, after 6, and 12 months: body weight, body mass index (BMI), systolic and diastolic blood pressure (SBP and DBP, respectively), fasting plasma glucose (FPG), fasting plasma insulin (FPI), HOMA index, lipid profile, adiponectin (ADN), resistin (r), retinol binding protein-4 (RBP-4), vaspin, visfatin, omentin, and chemerin. Furthermore, at the baseline, and after 6 and 12 months, patients underwent an euglycemic, hyperinsulinemic clamp to assess M value. Results: SBP and DPB were better decreased by olmesartan/amlodipine combination compared to amlodipine and olmesartan monotherapies (p< 0.01 for both). No variations of lipid profile were recorded in neither of the three groups. There was a decrease of FGP with olmesartan/amlodipine combination after 12 months compared to amlodipine monotherapy (p< 0.05). Olmesartan/amlodipine combination decreased FPI and HOMA index both compared to baseline (p< 0.05), and compared to olmesartan and amlodipine monotherapies (p< 0.05 for both), that did not alter these parameters. The olmesartan/amlodipine combination gave an increase of M value after 12 months, both compared to baseline (p< 0.01), to olmesartan monotherapy (p< 0.05), and to amlodipine monotherapy (p< 0.01). Both olmesartan, and olmesartan/amlodipine increased ADN and reduced r (p< 0.01 vs baseline, for both), without significant differences between the two groups. Olmesartan/amlodipine gave a decrease of both visfatin and vaspin after 12 months (p< 0.05, and p< 0.01 respectively), even if no differences in group to group comparison were observed. None of treatments influenced RBP-4 levels. Finally, olmesartan/amlodipine significantly decreased chemerin and omentin compared to single therapies (p< 0.05 for both). Conclusions: Other than to be more effective in reducing blood pressure, olmesartan/amlodipine single pill combination gave also a major increase of insulin sensitivity and a decrease of insulin resistance parameters compared to single monotherapies.