Measuring the efficacy of antihypertensive therapy by ambulatory blood pressure monitoring in the primary care setting

doi:10.1016/j.ahj.2005.02.014

American Heart Journal

Volume 151, Issue 1, January 2006, Pages 176-184

https://doi.org/10.1016/j.ahj.2005.02.014 Get rights and content

Background

Traditional clinical trials in hypertension measure the efficacy of antihypertensive drugs but may not fully assess their effectiveness in clinical practice. Community-based trials can provide this information but are limited because usually they are of open-label design and potentially subject to observer bias. Therefore, we used ambulatory blood pressure monitoring (ABPM), an automated and objective measure of blood pressure (BP) to overcome these shortcomings in a large community-based trial.

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 BP remained ≥140/85 mm Hg, the dose was increased to 80 mg, and if necessary, hydrochlorothiazide 12.5 mg was added after a further 4 weeks and continued for the final 4-week period. Baseline and treatment ABPM measurements were completed in 940 previously untreated patients and 675 previously treated patients.

Results

The average reduction of the entire cohort was −10.7/−6.5 mm Hg (P < .0001; mean 24-hour BPs were reduced by 12/8 and 8/5 mm Hg in the untreated and previously treated patients, respectively). In contrast, the office BPs fell by an average of 23/12 and 17/10 mm Hg in previously untreated and treated patients. In 401 patients whose baseline 24-hour BP was ≥130/85 mm Hg, the mean decrease in 24-hour BP was 16.8/11.4 mm Hg. Based on ABPM criteria, the BP was fully controlled (<130/85 mm Hg) in 70% of patients, and based on office measurement criteria (<140/90 mm Hg), in 79%.

Conclusions

Ambulatory BP monitoring demonstrated excellent control rates by telmisartan monotherapy or in combination with hydrochlorothiazide. Observer and measurement bias was substantial based on the changes from baseline by clinical measurements in contrast to ambulatory BP recordings. The successful use of this procedure in primary care research will create further opportunities to define the effectiveness of treatment in the environment in which it is customarily prescribed.

Section snippets

Study design

The MICCAT 2 was conducted from January to September of 2003 as a prospective, open-label, phase IV, community-based trial, designed to evaluate the antihypertensive efficacy of telmisartan and telmisartan with HCT on 24-hour BP control in patients with essential hypertension. ABPM was used to record each patient's BP over 24 continuous hours to measure the effects of telmisartan. To reduce bias, the study used a remote data transfer design such that the investigators were blinded to the

Study population

Six hundred forty practitioners enrolled a total of 2888 patients with hypertension. Of these, 2678 completed the initial screening visit, and 1842 completed the study. Thirty-one percent of the 2678 screened patients discontinued during the course of the study. The major reasons for patient discontinuations include subject withdrew consent (8.9%), noncompliance to study protocol (7.0%), AEs (5.9%), and lost to follow-up (2.7%). The population used for safety analysis consisted of the 2477

Principal findings

This large-scale community-based trial involving 600 office practices demonstrated that ABPM procedures could be successfully carried out in >1600 patients in a research protocol geared toward the primary care environment. Thus, this relatively sophisticated technique can be performed effectively by internists and family practitioners and perhaps should no longer be regarded as predominantly the domain of the hypertension specialist. Quite apart from being used to access the efficacy of therapy

Office and ambulatory BP findings

The criterion for patient entry into the study was by office BP rather than by ABPM. Typically, ambulatory BP values—which are usually expressed as the average of all readings obtained over a 24-hour period—are lower than office readings, largely because the ABPM data include nighttime values that, in most people, are substantially lower than daytime values. It has been calculated that to correspond with the office BP criterion of hypertension, usually 140/90 mm Hg or higher,3, 4 the ambulatory

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Telmisartan is an antagonist of the angiotensin II receptor used in the management of hypertension (alone or in combination with other antihypertensive agents. It belongs to the drug class of angiotensin II receptor blockers (ARBs). Among drugs of this class, telmisartan shows particular pharmacologic properties, including a longer half-life than any other angiotensin II receptor blockers that bring higher and persistent antihypertensive activity. In hypertensive patients, telmisartan has superior efficacy than other antihypertensive drugs (losartan, valsartan, ramipril, atenolol, and perindopril) in controlling blood pressure, especially towards the end of the dosing interval. Telmisartan has a partial PPARγ-agonistic effect whilst does not have the safety concerns of full agonists of PPARγ receptors (thiazolidinediones). Moreover, telmisartan has an agonist activity on PPARα and PPARδ receptors and modulates the adipokine levels. Thus, telmisartan could be considered as a suitable alternative option, with multi-benefit for all components of metabolic syndrome including hypertension, diabetes mellitus, obesity, and hyperlipidemia. This review will highlight the role of telmisartan in metabolic syndrome and the main mechanisms of action of telmisartan are discussed and summarized. Many studies have demonstrated the useful properties of telmisartan in the prevention and improving of metabolic syndrome and this well-tolerated drug can be greatly proposed in the treatment of different components of metabolic syndrome. However, larger and long-duration studies are needed to confirm these findings in long-term observational studies and prospective trials and to determine the optimum dose of telmisartan in metabolic syndrome.
Lifestyle modification for resistant hypertension: The TRIUMPH randomized clinical trial
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Resistant hypertension (RH) is a growing health burden in this country affecting as many as 1 in 5 adults being treated for hypertension. Resistant hypertension is associated with increased risk of adverse cardiovascular disease (CVD) events and all-cause mortality. Strategies to reduce blood pressure (BP) in this high-risk population are a national priority.
TRIUMPH is a single-site, prospective, randomized clinical trial to evaluate the efficacy of a center-based lifestyle intervention consisting of exercise training, reduced sodium and calorie Dietary Approaches to Stop Hypertension eating plan, and weight management compared to standardized education and physician advice in treating patients with RH. Patients (n = 150) will be randomized in a 2:1 ratio to receive either a 4-month supervised lifestyle intervention delivered in the setting of a cardiac rehabilitation center or to a standardized behavioral counseling session to simulate real-world medical practice. The primary end point is clinic BP; secondary end points include ambulatory BP and an array of CVD biomarkers including left ventricular hypertrophy, arterial stiffness, baroreceptor reflex sensitivity, insulin resistance, lipids, sympathetic nervous system activity, and inflammatory markers. Lifestyle habits, BP, and CVD risk factors also will be measured at 1-year follow-up.
The TRIUMPH randomized clinical trial (ClinicalTrials.gov NCT02342808) is designed to test the efficacy of an intensive, center-based lifestyle intervention compared to a standardized education and physician advice counseling session on BP and CVD biomarkers in patients with RH after 4 months of treatment and will determine whether lifestyle changes can be maintained for a year.
Assessment of drug-induced increases in blood pressure during drug development: Report from the Cardiac Safety Research Consortium
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This White Paper, prepared by members of the Cardiac Safety Research Consortium, discusses several important issues regarding the evaluation of blood pressure (BP) responses to drugs being developed for indications not of a direct cardiovascular (CV) nature. A wide range of drugs are associated with off-target BP increases, and both scientific attention and regulatory attention to this topic are increasing. The article provides a detailed summary of scientific discussions at a Cardiac Safety Research Consortium–sponsored Think Tank held on July 18, 2012, with the intention of moving toward consensus on how to most informatively collect and analyze BP data throughout clinical drug development to prospectively identify unacceptable CV risk and evaluate the benefit-risk relationship. The overall focus in on non-CV drugs, although many of the points also pertain to CV drugs. Brief consideration of how clinical assessment can be informed by nonclinical investigation is also outlined. These discussions present current thinking and suggestions for furthering our knowledge and understanding of off-target drug-induced BP increases and do not represent regulatory guidance.
The influence of age on blood pressure evaluation of hypertensive subjects
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The aim of this study was to determine whether age influences the concordance between different methods of blood pressure (BP) measurement and ambulatory BP monitoring (ABPM) in hypertensive subjects. We studied two groups: I, individuals younger than 50 years (n = 57), and II, individuals aged 60 years or older (n = 55). They were submitted to the performance of one ABPM, office BP measurements, home BP monitoring (HBPM), and BP measurements at a public health center (PHCBP). Student's t-test, Fisher's test and Lin coefficient were calculated. For Group II, systolic and diastolic pressures measured by HBPM were higher than by day ABPM (p < 0.01). The concordance between day ABPM and the other methods was lower for Group II than for Group I. There was a good concordance between systolic day ABPM and office BP, and between systolic ABPM and PHCBP only for Group I (Lin coefficient = 0.71 and 0.73). Group II reported better sleep quality after ABPM (p < 0.05). Considering 24-h ABPM, 52.6% of Group I and 29% of Group II were controlled (p < 0.01). Concluding, there was worse concordance between different methods of BP measurements and day ABPM in the older group, which had lower hypertension control rate and better tolerance of ABPM.
When and how to use self (home) and ambulatory blood pressure monitoring
2010, Journal of the American Society of Hypertension
Citation Excerpt :
A schema showing how both self/home and ambulatory BP measurements may be used in clinical practice is shown in the Figure. Self-BP monitoring may be used as an initial step to evaluate the out-of-office BP, and if ABPM is available it is most helpful in cases where the self/home BP is borderline (between 125/75 mm Hg and 135/85 mmHg).27,29,30 The target BP for self/home BP is usually 135/85 mm Hg for those whose target office BP is 140/90 mm Hg and 125/75 to 130/80 mm Hg for those whose target office BP is 130/80 mm Hg.29
This American Society of Hypertension position paper focuses on the importance of out-of-office blood pressure (BP) measurement for the clinical management of patients with hypertension and its complications. Studies have supported direct and independent associations of cardiovascular risk with ambulatory BP and inverse associations with the degree of BP reduction from day to night. Self-monitoring of the BP (or home BP monitoring) also has advantages in evaluating patients with hypertension, especially those already on drug treatment, but less is known about its relation to future cardiovascular events. Data derived from ambulatory BP monitoring (ABPM) allow the identification of high-risk patients, independent from the BP obtained in the clinic or office setting. While neither ABPM nor self-BP monitoring are mandatory for the routine diagnosis of hypertension, these modalities can enhance the ability for identification of white-coat and masked hypertension and evaluate the extent of BP control in patients on drug therapy.
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Clinical InvestigationPrevention and RehabilitationMeasuring the efficacy of antihypertensive therapy by ambulatory blood pressure monitoring in the primary care setting

Background

Methods

Results

Conclusions

Section snippets

Study design

Study population

Principal findings

Office and ambulatory BP findings

Lancet

Clin Ther

Lancet

Lancet

Am J Hypertens

Am J Hypertens

Am J Hypertens

Am J Hypertens

Am J Hypertens

Am J Cardiol

Age-specific relevance of usual BP to vascular mortality: a meta-analysis of individual data for one million adults in 60 prospective studies

Lancet

The seventh report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High BP

JAMA

Clinical Investigation
Prevention and Rehabilitation
Measuring the efficacy of antihypertensive therapy by ambulatory blood pressure monitoring in the primary care setting