Comparison of 24-Hour Ambulatory Central Blood Pressure Reduction Efficacy Between Fixed Amlodipine or Up-Titrated Hydrochlorothiazide Plus Losartan: The K-Central Study.

Objective: The main objective of this study was to evaluate non-inferiority of office mean systolic blood pressure (BP) reduction efficacy and superiority of 24-hour ambulatory central BP reduction efficacy between losartan combined with fixed dose amlodipine (L/A group) and dose up-titrated hydrochlorothiazide (L/H group) according to office BP.

Methods: We conducted a prospective, randomized, double-blind multicenter trial in 231 patients with hypertensive (mean age = 59.2 ± 12.2 years). Patients received losartan 50 mg monotherapy for 4 weeks, followed by additional use of amlodipine 5 mg or hydrochlorothiazide 12.5 mg for 20 weeks after randomization. The patients who did not achieve the BP goal after 4 weeks' randomization received an increased dose of 100 mg/5 mg for the L/A group and 100 mg/25 mg for L/H group, respectively. The 24-hour ambulatory central BP was measured at baseline and after 20 weeks' treatment.

Results: Office mean systolic BP reduction of L/A group was not inferior to L/H group after 4 weeks' treatment (-17.6 ± 13.3 vs. -14.4 ± 12.6 mm Hg, P = 0.0863) and was not significantly different after 20 weeks' treatment. (-15.7 ± 14.0 vs. -14.7 ± 15.1 mm Hg, P = 0.6130) The 24-hour ambulatory central systolic BP was significantly more reduced in the L/A group compared with that in the L/H group after 20 weeks' treatment (-9.37 ± 10.67 vs. -6.28 ± 10.50 mm Hg, P = 0.0407). The 24-hour ambulatory central systolic BP at the completion of the study and its reduction magnitude were independently associated with reductions in aortic pulse wave velocity, pulse pressure, and wave reflection magnitude.

Conclusion: Office systolic BP reduction with L/A was not inferior to L/H after 4 week's treatment. The combination of losartan and amlodipine was more favorable in 24-hour ambulatory central hemodynamics beyond BP-lowering efficacy than the combination of losartan and hydrochlorothiazide, regardless of office BP.

Clinical Trials Registration: NCT02294539.