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J Clin Hypertens (Greenwich). 2010;12:666–677. ©2010 Wiley Periodicals, Inc.
Hypertensive patients with cardiovascular (CV) comorbidities are at increased risk, and cardiologists’ care should put particular emphasis on controlling blood pressure. Data on blood pressure treatment and control and drug utilization on a global scale, however, are scarce. Aiming to resolve this lack of information, the authors analyzed the data of International Survey Evaluating Microalbuminuria Routinely by Cardiologists in Patients With Hypertension (i-SEARCH) to gain further insights into national and regional blood pressure control and antihypertensive pharmacotherapy prescribed in cardiology practice. A total of 22,282 patients with hypertension from 26 countries were enrolled in 2005/2006. A total of 18,652 patients were treated (mean age, 63.0±11.4 years; 52.2% male; mean body mass index, 28.9 kg/m2). Mean systolic blood pressure was 148.2±19.8 mm Hg and diastolic blood pressure was 86.7±11.6 mm Hg. Blood pressure was controlled in 8.3% of diabetic and 25.3% of nondiabetic patients (21.2% overall), with particularly good control rates in North and Latin America (28.0% and 30.6%, respectively). A total of 31.2% of patients were treated with 1, 39.7% with 2, and 29.1% with ≥3 drugs. β-Blockers were being used most frequently (47.9%), in both monotherapy and combination therapy despite low numbers of patients with respective compelling indications for their use. The present data illustrate the potential for an improvement of blood pressure treatment and control in daily cardiology practice.
Hypertension is responsible for the majority of CV morbidity and mortality worldwide1 and is one of the most important reasons for office visits to physicians.2 It has also been regarded as a barometer for the quality of a health care system.3 Despite the availability of a large number of effective and well-tolerated antihypertensive drugs,4 however, blood pressure (BP) control rates are not satisfactory on a national and global scale.5–8 This holds especially true for the general population in Europe compared with the Americas.9
Efforts to effectively improve BP control should be based on an in-depth knowledge of patient characteristics and the relative contribution of the treating physicians.10 Therefore, the role of physicians’ attitudes and practice patterns (detection, treatment, and management of hypertension) has received increased attention.3,11,12 We have recently reported results from a survey in 1259 primary care physicians worldwide,8 showing that (1) physicians tend to overestimate control rates; (2) physicians make only limited efforts to control BP at BP values close to normal, although the elevated CV risk of hypertension was acknowledged; and (3) there is a lack of awareness on the patient side, being responsible for the apparent mismatch between hypertension treatment efforts and control rates.8 An important but obviously largely neglected aspect of this, however, is the choice and intensity of antihypertensive treatments in routine care. To our knowledge, there are no or only regionally restricted major drug utilization studies that directly link the patient’s diagnosis to actual treatment patterns.13
In aiming to provide such data, we analyzed recent cross-sectional data from the International Survey Evaluating Microalbuminuria Routinely by Cardiologists in Patients With Hypertension (i-SEARCH) to address the following questions: (1) What are the BP control rates in cardiology practice across a number of countries and regions worldwide; (2) what are the BP control rates in relation to concomitant CV risk factors and comorbidities; and (3) what kind of antihypertensive drug treatments are prescribed in relation to concomitant risk factors and disease.
Patients and Methods
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- Patients and Methods
Eligible patients were male and female outpatients, 18 years or older, treated by a cardiologist, with currently treated or newly diagnosed arterial hypertension, defined as a seated systolic/diastolic BP of ≥140/90 mm Hg by sphygmomanometry or automated validated devices after 5 minutes of rest on the day of the study visit. Patients with acute fever (>38°C), renal disease (serum creatinine >20 mg/L), or concomitant urinary tract infection; those receiving treatment with cimetidine; those having undertaken strenuous physical activity in the preceding 24 hours; and women who were pregnant or menstruating were ineligible (the study was conducted to assess the prevalence of microalbuminuria and these factors increase the likely presence of false-positive results for microalbuminuria). Institutional and ethical review board approval for the study was granted for all participating centers, and all patients gave written informed consent to study participation. The study was conducted in accordance with the ethical principles of the current Declaration of Helsinki and consistent with the International Conference on Harmonization Good Clinical Practice.
Study Design and Procedures
This was an international observational survey in which patients were evaluated during a single visit. To allow extrapolation of results to the broadest possible population, the physician selection procedure took into account geographic aspects in each country (West/East, South/North, urban/suburban/rural) and physician profile (office/hospital).
For the subsequent comparison of global hypertension control, participating countries were clustered into regions: Northern Europe (Belgium, Germany, Sweden, Switzerland), Southern Europe (Greece, Italy, Spain, Turkey), Europe (Northern and Southern Europe), North America (Canada), Middle East (Kuwait, Lebanon, Qatar, Saudi Arabia, United Arab Emirates), and Asia (Hong Kong, Indonesia, Korea, Singapore, Taiwan, Thailand, Vietnam).
At each site, consecutive patients fulfilling the eligibility criteria were invited to participate in the study. Once enrolled, the following measurements were carried out on each patient: heart rate, urinary albumin and creatinine concentrations, and waist and hip circumferences. Results from these assessments were entered on each patient’s case report form, together with demographic data, CV history, and presence of CV risk factors, comorbidities, symptoms and signs of CV disease, and current chronic drug therapy. Levels of cholesterol, triglycerides, high-density lipoprotein, low-density lipoprotein, C-reactive protein, and serum creatinine were included if they were assessed fewer than 12 months ago.14
BP control was defined as a random BP reading of ≤140/90 mm Hg in nondiabetic and ≤130/80 mm Hg in diabetic patients. CV comorbidities included a history of stroke, myocardial infarction (MI), coronary artery disease (CAD), left ventricular hypertrophy (Sokolov-Lyon index >35 mm), congestive heart failure, and atrial fibrillation. CV risk factors included diabetes mellitus, current smoking, known hyperlipidemia, a body mass index (BMI) >30 mg/m2, and a family history of CAD/MI. Diagnoses were based on the investigator’s assessment and were not further validated within this study.
Population characteristics that included demographics, medical history, nature, duration and severity of disease, comorbidities, and current or no treatment were summarized into means and standard deviations (SDs) for continuous variables and percentages (95% confidence intervals [CIs]) for categoric data.
A linear model was used to estimate the least square means of BP or number of antihypertensive treatment drugs according to region, adjusted for age, sex, diabetes, or plus number of comorbidities. A logistic regression analysis was conducted to estimate the BP control rate (adjusted probabilities) according to region, adjusted for age, sex, and diabetes, using predictive marginal probabilities. Continuous variables are depicted as adjusted means (least squares means) ± SDs and categoric variables as percentages (95% CIs).
Acknowledgments and disclosures: The authors would like to thank Sam Zhong for statistical support provided. The study was supported by Sanofi-Aventis, Paris, France. MT and WDP are employees of the sponsors of the study. PB, MB, MV, BVK, and UT have been consulting for Sanofi-Aventis and received speaker honoraria and research support.