Reproducibility Of Blood Pressure Measurements Research Articles

REPRODUCIBILITY OF OFFICE, HOME AND AMBULATORY BLOOD PRESSURE MEASUREMENTS IN CHILDREN AND ADOLESCENTS

Abstract Objective: To compare the reproducibility of blood pressure measurements taken in the office (OBP), at home (HBP) and with ambulatory monitoring (ABP) in children and adolescents. Design and method: Apparently healthy children and adolescents (age 6–18 years) referred for elevated BP were included. OBP was measured in 2 visits (triplicate auscultatory measurements), HBP on 7 days (duplicate morning and evening measurements) and 24 h ABP at 20-minute intervals. All measurements were repeated after 1–6 months. The reproducibility of OBP (visit 1 and 2), HBP (7 days) and ABP (24 h, daytime, nighttime) was quantified using test-retest correlations coefficients (r) and standard deviation of differences (SDD) between repeated measurements. Results: 58 subjects were included (mean age 13.0 ± 2.9 years, 60.3% boys, average interval between assessments 4.1 ± 2.1 months). All BP differences between sessions were non-significant apart from diastolic OBP at visit 1 (p < 0.05; Table). The reproducibility of HBP was comparable to that of 24 h ABP and both were superior to that of OBP. The reproducibility of 24 h ABP tended to be superior to that of daytime and nighttime values (Table). Similar conclusions were provided by SDD and r values. Conclusions: These data suggest that in children and adolescents out-of-office BP measurements are more reproducible than OBP measurements. 7-day HBP and 24 h ABP appear to have similar reproducibility.

Home Blood Pressure Measurements for Managing Hypertension in Hemodialysis Patients

Home blood pressure (BP) monitoring serves as a practical method to detect changes in BP instead of ambulatory BP monitoring in hemodialysis patients. To evaluate the relationship of reduction in home BP compared to interdialytic ambulatory BP measurements we analyzed the data from the dry-weight reduction in hypertensive hemodialysis patients (DRIP) trial in which 100 patients had their dry weight probed based on clinical sign and symptoms and 50 patients served as controls. We measured home BP 3 times a day for 1 week using a validated oscillometric monitor on 3 occasions at 4-week intervals after randomization. Changes from baseline in home, predialysis BP and postdialysis BP were compared to interdialytic 44-hour ambulatory BP. Home and ambulatory BP monitoring was available in 141 of 150 (94%) patients. Predialysis systolic BP was not as sensitive as ambulatory BP in detecting change in BP with dry-weight reduction. Whereas postdialysis BP was capable of detecting an improvement in systolic BP in response to probing dry weight, by itself it does not provide evidence that change in postdialysis BP persists over the interdialytic period. Home BP reliably detected changes in ambulatory BP, albeit with less sensitivity at 4 weeks. However, at 4 and at 8 weeks, changes in home systolic BP were most strongly related to changes in interdialytic ambulatory systolic BP compared to predialysis and postdialysis BP. The reproducibility of BP measurements followed the order home > ambulatory >> predialysis > postdialysis. These data provide support for the use of home BP monitoring for the management of hypertension in hemodialysis patients.

Response to Prognostic Significance of Between-Arm Blood Pressure Differences: Between-Arm Blood Pressure Difference and Mortality and the Interarm Blood Pressure Difference: Between-Arm Blood Pressure Differences Are Important

We thank Kleefstra et al1 for raising important questions about the methods and conclusions of our study.2 The blood pressure device that we used is now discontinued but is substantially equivalent to the HEM-442C Manual Inflation BP Monitor (John Winegardner, Omron Healthcare, written communication, 2005.). The automatic version HEM-432C, also known as the Omron M1 Classic Model, has been validated using the International Protocol of the Working Group on Blood Pressure Monitoring of the European Society of Hypertension.3 Reproducibility of blood pressure measurement is undoubtedly influenced by time. The longer we wait between measurements, the less reproducible the readings are likely to be. Thus, it is no surprise that reproducibility of measurements >1 year is less compared with those performed over 1 week. Because it is also likely that, over the longer term, progression of atherosclerotic disease or treatment of hypertension may influence the reproducibility of blood pressure measurements, the shorter-term reproducibility more likely reflects the true reproducibility of …

Limited (6-h) ambulatory blood pressure monitoring is a valid replacement for the office blood pressure by trained nurse clinician in the diagnosis of hypertension

To assess the ability of limited ambulatory blood pressure monitoring as a valid replacement for office blood pressure measurement done to American Heart Association criteria in diagnosing hypertension. In all, 105 adults, who had been referred for limited ambulatory blood pressure monitoring, participated in the study. Limited ambulatory blood pressure monitoring consisted of 6 h of blood pressure measurement while ambulatory at the Mayo Clinic, using a SpaceLabs 90207 (SpaceLabs Medical, Issaquah, Washington, USA) collecting six readings per hour for the period of observation. The study participants gave consent for three additional consecutive office blood pressure measurements, using a validated aneroid device, done to American Heart Association criteria, by a single hypertension nurse specialist. Mean systolic blood pressure by limited ambulatory blood pressure monitoring was 137.9+/-14.2 mmHg and for the nurse, 137.9+/-20.1 mmHg. Mean diastolic blood pressure by limited ambulatory blood pressure monitoring was 81.5+/-9.7 mmHg and for the nurse, 74.3+/-11.9 mmHg. The intermethod difference for systolic blood pressure was 0.03+/-12.5 mmHg and diastolic blood pressure, -7.2+/-8.0 mmHg. Using <140/90 as criteria factor, limited ambulatory blood pressure monitoring and the trained nurse agreed 77% of the time on whether the patient was hypertensive. This agreement increased to 81% if the participant's referral blood pressure was >or=140/90. Limited ambulatory blood pressure monitoring is an excellent replacement for office blood pressure, done to American Heart Association criteria, in diagnosing hypertension. This avoids issues of variability introduced by the observers, such as digit preference and bias, and increases reproducibility of blood pressure measurements. The appropriate normal value for limited ambulatory blood pressure monitoring is <140/90 mmHg compared with <135/85 mmHg used in 24-h ambulatory blood pressure monitoring.

Evaluation of the placebo effect and reproducibility of blood pressure measurement in hypertension

Pharmacologic studies in hypertension often describe blood pressure (BP) reductions in placebo control groups. This placebo effect is currently debated, as it seems to be related to BP measurement methods and as a regression to the mean phenomenon may lead to misinterpretation. Furthermore, data on pulse pressure are lacking. This study was designed to evaluate the placebo effect on BP and to differentiate it from regression to the mean. According to a crossover design, 26 mild-to-moderate hypertensive patients who were treated with placebo or given no treatment were followed-up for 1 month. Clinic and ambulatory BP was assessed at baseline and at the end of each 1-month period. Placebo administration resulted in significant reductions in clinic systolic, diastolic, and mean BP ( P < .01), ambulatory 24-h SBP ( P < .05), and daytime systolic, diastolic, and mean BP ( P < .01, P < .05, P < .01, respectively). No significant differences were noted for pulse pressure and heart rate or between BP values measured at baseline and after 1 month without treatment. Despite a significant correlation between changes in clinic and ambulatory BP, the scatter of individual data suggests that the placebo response observed with one method cannot be systematically extrapolated to the other method. This study conclusively shows the effect of placebo in mild-to-moderate hypertension on both clinic and ambulatory systolic, diastolic, and mean BP, in which it has been shown to differ from the regression to the mean phenomenon. This effect was not observed for pulse pressure or heart rate.

Reproducibility of ambulatory blood pressure measurements in essential hypertension.

Data on the reproducibility of serial measurements of ambulatory blood pressure in hypertensive patients are lacking. The purpose of this study was to examine (1) the reproducibility of four consecutive ambulatory blood pressure measurements, and (2) the reproducibility of nocturnal falls in blood pressure in hypertensive patients. Twenty patients with mild to moderate essential hypertension underwent four separate ambulatory blood pressure monitorings, on the same day of the week, at 30-day intervals. Antihypertensive therapy was discontinued for 2 weeks before each recording. Comparing the mean values of blood pressure over 24h, as well as diurnal, nocturnal and hourly periods, among the four recordings determined the reproducibility of blood pressure measurements. A day/night difference in mean systolic and in mean diastolic blood pressure defined the nocturnal fall in blood pressure. No significant differences were observed in either hourly, 24-h, diurnal or nocturnal systolic blood pressure, diastolic blood pressure and heart rate, or in the nocturnal fall in systolic and diastolic blood pressure among the four recordings. Hourly systolic blood pressure, diastolic blood pressure, heart rate, and nocturnal fall in blood pressure were reproducible in four ambulatory blood pressure monitorings recorded over 4 months. These findings suggest that ambulatory blood pressure monitoring is a reliable tool to monitor blood pressure changes.

Reproducibility of ambulatory and clinic blood pressure measurements in elderly hypertensive subjects.

To compare the reproducibility of clinic and ambulatory blood pressure measurements in elderly hypertensive subjects. Twenty-two untreated elderly hypertensives, with a clinic systolic blood pressure (SBP) > 160 mmHg and/or diastolic blood pressure (DBP) > 95 mmHg, and a mean age of 76 years (range 66-86). Following three supine clinic blood pressure readings the subjects underwent 24-h non-invasive ambulatory blood pressure monitoring, measurements being taken at 20-min intervals from 0700 to 2200 h and at 30-min intervals from 2200 to 0700 h. Measurements were repeated during a further visit at a median interval of 10 weeks (range 1-10 months). Daytime ambulatory SBP levels were 20 mmHg (95% confidence interval 14-27 mmHg, P < 0.001) lower than clinic SBP, although DBP values were similar. The mean 24-h ambulatory SBP and DBP reproducibility [assessed by the standard deviation of differences (SDD) between visits] was significantly better than that for mean clinic blood pressure (SBP 6.3 versus 17.4 mmHg, P < 0.001; DBP 4.8 versus 7.0 mmHg, respectively, P < 0.05). With daytime defined as 1000-1959 h, the SDD between visits was 12.4 mmHg for SBP and 8.3 mmHg for DBP, but with daytime defined as 0700-2159 h, the SDD fell to 6.0 mmHg for SBP and 4.8 mmHg for DBP, values almost identical to those obtained with full 24-h blood pressure monitoring. There was no difference in night-time blood pressure reproducibility, whether night-time was defined as 2400-0559 h or 2200-0659 h. Both 24-h and daytime ambulatory blood pressure monitoring significantly improve the reproducibility of blood pressure measurements compared with clinic blood pressure readings in elderly hypertensive subjects. Increasing the number of daytime blood pressure readings by 50% (from 30 to 45) reduced the variability of blood pressure measurement by 50%. Twenty-four-hour ambulatory blood pressure monitoring is of value in obtaining reproducible blood pressure measurements in elderly hypertensive subjects. However, more than 30 readings are needed during a daytime recording to significantly reduce variability compared with repeated clinic measurements, although night-time variability is not significantly affected if the number of readings is reduced to 12 over a 6-h period.