The importance of the clinical observer in the development of a white-coat effect in African-American patients with hypertension.

INTRODUCTION: As the office-awake blood pressure (BP) difference (white-coat effect) in African-Americans has not been evaluated, we studied the ethnicity, professional status (nurse versus doctor) and sex of the observer on the white-coat effect in African-American patients with hypertension. METHODS: Seated clinical BP measurements were obtained in random order by an African-American male research physician, a Caucasian male research physician, and a Caucasian female nurse who is of similar age and clinical experience. Within 1 week, ambulatory BP recordings were performed. RESULTS: A total of 65 African-American patients [54+/-13 years, 55% women, body mass index (BMI) 31+/-6 kg/m, 62% on drug therapy, 28% current smokers] participated in the study. Twenty-two percent had a systolic white-coat effect >20 mmHg and 49% had a diastolic white-coat effect >10 mmHg (average of all observers). Although there were no differences in the magnitude of the white-coat effect among the three study observers, the primary physician's diastolic white-coat effect was significantly greater than that of the African-American physician (14+/-12 vs. 9+/-12, P=0.05), but not the systolic white-coat effect (16+/-16 vs. 10+/-16 mmHg, P=0.09). BMI positively correlated with the systolic and diastolic white-coat effect (r=0.30, P=0.02 and r=0.41, P=0.0001), but this correlation was true only for female patients in multiple regression analyses. BMI significantly predicted the systolic (P=0.043) and diastolic (P=0.004) white-coat effects. CONCLUSION: A white-coat effect is relatively common in African-American patients with hypertension and is the largest when the observer is their usual doctor. The clinical observer's ethnicity or sex does not play an important role in generating a white-coat effect in African-American patients with hypertension.

Effects of metoprolol succinate extended release vs. amlodipine besylate on the blood pressure, heart rate, and the rate-pressure product in patients with hypertension.

Ambulatory monitoring of the blood pressure (BP) and heart rate allows for the assessment of the 24-hour rate-pressure product (RPP), a close correlate of myocardial oxygen demand, both in the untreated state and while on antihypertensive therapy. To evaluate the clinical effects of metoprolol succinate extended release (ER) tablets (100 mg titrated to 200 mg for clinic BP >140/90 mm Hg) vs. amlodipine (5 mg titrated to 10 mg for clinic BP >140/90 mm Hg) on the 24-hour and early morning hemodynamic parameters, we performed a double-blind crossover trial that included 8 weeks of active treatment, 4 weeks of placebo washout, and 8 weeks of active crossover treatment using 24-hour ambulatory blood pressure (ABP) measurements. Patients were included if they were untreated, had hypertension based on both clinic (140 to 179/90 to 109 mm Hg) and ABP recordings (>135/85 mm Hg while awake), and were 18 to 65 years of age. Patients enrolled in the trial (n = 35) had a mean age of 55 +/- 7 years, 24-hour mean BP of 148/91 +/- 11/7 mm Hg, heart rate (HR) of 76 +/- 10 beats/minute, and a RPP of 11,230 +/- 1717 mm Hg.beats.minute). In the early morning period (6 am to 10 am), baseline BP was 155/98 +/- 11/7 mm Hg and the RPP was 12,084 +/- 1752 mm Hg.beats.minute. The 24-hour diastolic blood pressure (DBP), HR, and RPP were lowered to a greater extent by metoprolol succinate compared with amlodipine. Additionally, changes from baseline in early morning DBP, HF, and RPP were lowered to a significantly greater extent by metoprolol (mean dose, 124 +/- 44 mg daily) compared with amlodipine (mean dose, 7.2 +/- 2.5 mg daily) (P = .02 for DBP and P < .0001 for HR and the RPP). The incident rates of adverse events were low and similar for the two treatment groups. These data demonstrate that metoprolol succinate ER induced greater reductions in early morning BP, HR, and FPP than amlodipine in middle-aged patients with Stages 1 and 2 hypertension. These findings have clinical implications for patients with hypertension and coronary heart disease.

Clinical evaluation of the Trimline blood pressure cuffs with the Accutorr Plus Monitor.

BACKGROUND: Non-invasive blood pressure (BP) monitoring has become increasingly popular. To assure the accuracy of devices used for this purpose, these devices should be clinically validated using standard criteria such as those published by the Association for the Advancement of Medical Instrumentation (AAMI). The purpose of this study was to collect and assess non-invasive BP data using the Trimline BP cuffs (Branchburg, New Jersey, USA) with the Accutorr Plus Monitor (Datascope Corp., Mahwah, New Jersey, USA) in accordance with AAMI standards. METHODS: Blood pressure measurements taken employing this device were compared with the results obtained by two experienced observers using a mercury sphygmomanometer on 109 subjects (545 measurements). The limits of agreement were calculated for the device compared with the results of the two observers according to the AAMI standards. RESULTS: The agreement parameters between the two observers were -0.49+/-3.81 mmHg for systolic BP and 0.50+/-3.19 mmHg for diastolic BP. The agreement between the device and the observers was -0.13+/-7.51 and 2.54+/-5.21 mmHg for systolic and diastolic BP, respectively. The proportions of observer and device values agreeing within 5, 10, and 15 mmHg were 65, 87, and 94% for systolic BP and 72, 93, and 97% for diastolic BP. CONCLUSIONS: The Trimline BP cuffs in conjunction with the Accutorr Plus device demonstrated acceptable accuracy and precision in accordance with the AAMI criteria for a non-invasive BP monitoring device.

Evaluation of the overall system precision of the Welch-Allyn transtelephonic home blood pressure monitor in adults with Parkinson's disease.

BACKGROUND: Non-invasive blood pressure (BP) devices should be independently evaluated before being used in special populations. The objective of this study was to assess the accuracy of the Welch-Allyn transtelephonic home blood pressure monitor in adults with Parkinson's disease to evaluate the device for use in a large clinical trial involving the safety and efficacy of a monoamine oxidase inhibitor. METHODS: BP measurements taken with the device were compared with the results obtained by two experienced observers using a mercury sphygmomanometer in patients with Parkinson's disease. The limits of agreement were then calculated for the device and compared with the results of the two observers. RESULTS: The agreement parameters between the two observers were -0.5 +/- 2.6 mmHg for systolic BP and 0.1 +/- 2.2 mmHg for diastolic BP. The agreement between the Welch-Allyn transtelephonic device and the observers was -2.6 +/- 4.5 mmHg and -1.9 +/- 3.2 mmHg for systolic and diastolic BP respectively. Nearly 90% of the readings were within 10 mmHg of the observers for both systolic and diastolic BP. Mild tremor had a moderate effect on the validity of the device. CONCLUSIONS: The Welch-Allyn transtelephonic device demonstrated acceptable precision in this cohort of patients with Parkinson's disease and is considered valid for use in a clinical trial involving these patients.