Defining the antihypertensive properties of the angiotensin receptor blocker telmisartan by a practice-based clinical trial.

Traditional randomized controlled clinical trials are designed to define the specific properties of individual antihypertensive drugs but do not provide full information about their use in clinical practice. To carry out a large-scale practice-based open-label trial to evaluate the safety and efficacy of an angiotensin receptor blocker (ARB) in controlling blood pressure (BP) in the community setting, 703 practitioners recruited 2705 hypertensive patients. There were three groups: untreated at the time of study entry with uncontrolled BP (>/=140/90 mm Hg) (N = 1957); treated but uncontrolled on current monotherapy (N = 685); and treated and controlled, but with unacceptable side effects (N = 63). After stopping any previous treatment, patients received telmisartan (40 mg daily) for 2 weeks; the dose was increased to 80 mg if BP remained >/=130/85 mm Hg. Participants were then followed for a further 4 weeks. Blood pressure decreased by 18.9/12.3 mm Hg in the untreated group, by 13.1/7.9 mm Hg in the previously treated but uncontrolled group, and increased slightly by 3.5/1.3 mm Hg in the previously controlled group. Patients not responding adequately to the 40-mg telmisartan dose had an initial BP reduction of 7.3/4.5 mm Hg; titration to 80 mg gave an additional 7.5/5.0 mm Hg reduction and controlled BP (<140/90 mm Hg) in 44% of these titrated patients. Overall, control occurred in 56% of white patients; 52% of black patients (who responded well to dose titration); 60% of patients <65 years; and 46% of patients >/=65 years. Thus, in contrast with the relatively flat dose response effects in controlled parallel group trials, this practice-based trial has demonstrated the value of titrating telmisartan to its maximum dose in patients with inadequate BP responses to the initial dose, and has shown its efficacy across major demographic groups.