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

BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.