Background: Twenty-four-hour ambulatory blood pressure monitoring (ABPM) has been shown to be more reliable than conventional measurements for hypertension assessment and the associated increased risk of cardiovascular events. Olmesartan/hydrochlorothiazide combination therapy has demonstrated increased blood pressure lowering over 24 hours compared with the component monotherapies. This prespecified pooled analysis of data from two trials investigated the effects of olmesartan/hydrochlorothiazide combination therapy and olmesartan monotherapy on 24-hour blood pressure control in patients with moderate-to-severe hypertension.
Methods: After 8 weeks' open-label olmesartan 40 mg monotherapy, uncontrolled patients (mean trough seated blood pressure 90-115/140-180 mmHg and 24-hour mean ambulatory diastolic blood pressure ≥80 mmHg with ≥30% of daytime ambulatory diastolic blood pressure readings >85 mmHg) were randomised to 8 weeks' double-blind treatment with olmesartan 40 mg or olmesartan/hydrochlorothiazide 20/12.5, 40/12.5 or 40/25 mg (Study 1) or olmesartan/hydrochlorothiazide 20/25 or 40/25 mg (Study 2). This prespecified analysis of ambulatory blood pressure was performed on patients from the full analysis set of pooled studies 1 and 2, restricted to patients who provided at least one valid ABPM measurement at baseline.
Results: After 8 weeks' double-blind treatment, reductions in 24-hour, daytime and night-time blood pressure from baseline were observed for all treatment groups. These reductions were dose-dependent, with olmesartan/hydrochlorothiazide 40/25 mg demonstrating the greatest reductions in 24-hour blood pressure from baseline to Week 16 versus olmesartan monotherapy: -14.0/-8.8 vs -2.7/-2.0 mmHg, respectively; p < 0.0001.
Conclusions: Adding hydrochlorothiazide to olmesartan provides more effective 24-hour blood pressure control versus olmesartan monotherapy in patients with moderate-to-severe hypertension.
Clinical trial registration: Study 1: EudraCT Number: 2006-003876-37; ClinicalTrials.gov identifier: NCT00430508; Study 2: EudraCT Number: 2006-003876-28; ClinicalTrials.gov identifier: NCT00430950.