Ambulatory blood pressure monitoring in the primary care setting: assessment of therapy on the circadian variation of blood pressure from the MICCAT-2 Trial

Abstract

We conducted a large-scale, practice-based trial (MICCAT-2) to evaluate the effects of telmisartan alone and in combination with a diuretic on 24-h blood pressure (BP) profiles, including the early morning period, a time when cardiovascular risk is excessive. Patients with hypertension, either untreated or currently on treatment, were started on, or switched to, the angiotensin receptor blocker telmisartan 40 mg daily; after 2 weeks, if office blood pressure (BP) remained > or =140/85 mmHg, the dose was increased to 80 mg; and if necessary, hydrochlorothiazide 12.5 mg was added after a further 4 weeks and continued for a final 4-week period. Twenty-four-hour ambulatory blood pressure monitoring (ABPM) was performed at baseline and at the end of the treatment period. Baseline and treatment ABPM measurements were completed in 1619 patients. There were highly significant reductions in both the daytime (-11.8/-7.2 mmHg) and night-time (-9.6/-5.7 mmHg) mean BP following telmisartan alone or in combination with the diuretic. Evaluation of the 24-h profiles showed evidence for sustained pharmacodynamic effects of telmisartan over the entire dosing period. Ninety-five (6%) patients had a marked surge in early morning BP defined as >30 mmHg post-awakening change in systolic BP. The average reduction of in the early morning (post-awakening) BP in the entire cohort was -11.5/-7.0 mmHg (P<0.001; reductions were similar for monotherapy and combination therapy groups. The early morning post-awakening BPs fell by an average of -17.2/-10.1 mmHg in patients with large morning BP surges (P<0.05 versus non-surge patients). In a community based study using ambulatory BP monitoring, telmisartan-based therapy induced highly significant reductions in systolic and diastolic BP over 24 h and was particularly effective in reducing BP during the early morning period.