Discordant prevalence of hypertension using two different automated blood pressure measurement devices: a population-based study in Dar es Salaam (Tanzania)

Patient preferences for ambulatory blood pressure monitoring devices: Wrist-type or arm-type?

BACKGROUND

Ambulatory blood pressure monitoring (ABPM) is important in evaluating average 24-hour blood pressure (BP) levels, circadian rhythm, sleeping BP and BP variability but many patients are reluctant to use standard ABPM devices.

METHODS

We compared two validated ABPM devices, the BPro tonometric wrist monitor and the A&D TM-2430 oscillometric upper arm monitor, for agreement of recordings and acceptability in 37 hypertensive patients (aged 55±9 years).

RESULTS

Successful BP measurements were less frequent with the wrist-type than the arm-type device during the sleeping (66.3% vs. 92.9%, P <0.01) and awake periods (56.2% vs. 86.5%, P <0.01). Comparable paired readings showed no significant difference in systolic BP but diastolic BP (DBP) values were higher with the wrist compared to the arm monitor (24-hour 89±13 vs. 85±14 mmHg, P <0.01) with similar differences awake and sleeping. Bland-Altman analysis showed some large discrepancies between individual arm and wrist monitor measurements. More patients found the wrist monitor more comfortable to use than the arm monitor.

CONCLUSIONS

Despite the difference in individual BP measurements and the systematic overestimation of DBP values with the BPro device, wrist monitors with good patient acceptability may be useful to facilitate ABPM in some patients to provide additional information about cardiovascular risk and response to antihypertensive therapies.

Evaluation and effects of the Omron 725 CIC device for measuring blood pressure in a hypertension clinic

BACKGROUND

We compared the Omron 725 CIC device (Omron Healthcare Inc., Vernon Hills, Illinois, USA), which is designed to register the blood pressure on the arm, with a mercury sphygmomanometer. In addition, we evaluated the possible impact that this device might have on the decisions made in a hypertension clinic.

METHODS

Patients (n=183) older than 18 years (range 18-84 years) with a wide range of systolic (87-197 mmHg) and diastolic (48-108 mmHg) blood pressures were included. Some of the standards of the Association for the Advancement of Medical Instrumentation and of the British Hypertension Society were used to evaluate the results of the automated device in clinical practice.

RESULTS

Using Bland-Altman analysis, an underestimation of both measures was observed with the automated Omron 725 CIC device; the systolic pressure was 3.6+/-8.8 mmHg too low with a very wide range of -13.7 to 20.9 and the diastolic pressure was also 4.4+/-6.3 mmHg too low with a range of -8.1 to 16.9. Clinical decisions could have been changed in 24 of the 116 hypertensive patients (20.6%) if the readings of the automated device had been used instead of using the readings of a mercury sphygmomanometer. These could have included modifying the dosage or changing the medicine used.

CONCLUSION

The blood pressure measurements by Omron 725 CIC are different from those of blood pressure readings taken with a mercury sphygmomanometer and this could affect clinical decisions in the diagnosis and follow-up of a hypertensive patient in an office environment.

Has blood pressure increased in children in response to the obesity epidemic?

The associations between elevated blood pressure and overweight, on one hand, and the increasing prevalence over time of pediatric overweight, on the other hand, suggest that the prevalence of elevated blood pressure could have increased in children over the last few decades. In this article we review the epidemiologic evidence available on the prevalence of elevated blood pressure in children and trends over time. On the basis of the few large population-based surveys available, the prevalence of elevated blood pressure is fairly high in several populations, whereas there is little direct evidence that blood pressure has increased during the past few decades despite the concomitant epidemic of pediatric overweight. However, a definite conclusion cannot be drawn yet because of the paucity of epidemiologic studies that have assessed blood pressure trends in the same populations and the lack of standardized methods used for the measurement of blood pressure and the definition of elevated blood pressure in children. Additional studies should examine if favorable secular trends in other determinants of blood pressure (eg, dietary factors, birth weight, etc) may have attenuated the apparently limited impact of the epidemic of overweight on blood pressure in children.

Difference in Blood Pressure Readings with Mercury and Automated Devices: Impact on Hypertension Prevalence Estimates in Dar es Salaam, Tanzania

OBJECTIVES

(1) To compare blood pressure (BP) readings with an automated arm cuff oscillometric device (AutoBP) to readings with a mercury sphygmomanometer (HgBP) and (2) to evaluate the impact on the prevalence of hypertension (HBP) in a population-based survey.

METHODS

(1) In a convenience sample ("Comparison Study"), we measured BP with both AutoBP (Visomat OZ2) and HgBP and we modeled BP difference (DeltaBP = HgBP-AutoBP) with multiple regression analysis. (2) Using DeltaBP, we calculated HgBP in a survey previously conducted in Dar es Salaam ("Population Survey") in which BP was measured with the automatic device Visomat OZ2 and we compared the prevalence of HBP (> or =140/90 mmHg or treatment).

RESULTS

In the Comparison Study (404 subjects aged 25-64), systolic/diastolic BP was higher by 4.4/4.7 mmHg (SE: 0.4/0.3) with HgBP than AutoBP. The prevalence of HBP was 42% with HgBP and 36% with AutoBP (relative difference of 14%). DeltaBP was associated with age, BP and arm circumference. In the Population Survey (9.254 subjects aged 25-64), the prevalence of HBP was 17% with calculated HgBP and 14% with AutoBP (relative difference of 20%).

CONCLUSION

A small systematic bias in BP readings between two different devices had large impact on hypertension prevalence estimates. This suggests that automated devices used in epidemiological studies should be validated with particular care.

Validation of the Omron 637IT wrist blood pressure measuring device with a position sensor according to the International Protocol in adults and obese adults

OBJECTIVE

Wrist blood pressure devices are becoming popular for the self-measurement of blood pressure. Despite widespread use of these devices, there is limited published evidence for their accuracy and reliability. In this study, we assessed the accuracy of the Omron 637IT wrist blood pressure device against the mercury sphygmomanometer in adults and obese adults according to the International Protocol criteria.

METHODS

A hundred and thirty-one participants were studied and classified on the basis of the International Protocol range. Blood pressure measurements at the wrist using the Omron 637IT were compared with the results obtained by two trained observers using a mercury sphygmomanometer. Nine sequential blood pressure measurements were taken. Initially, 33 participants with random arm circumferences were selected for the first validation study. Then, the device was evaluated in adults with arm circumferences equal to or higher than 34 cm. During each validation study, 99 measurements were obtained for comparison from the 33 participants. The first phase was performed on 15 participants, and, if the device passed this phase, 18 more participants were selected.

RESULTS

Mean discrepancies and standard deviations of the sphygmomanometer device were 0.5+/-6.2 mmHg for systolic blood pressure and 0.1+/-3.7 mmHg for diastolic blood pressure in the adult group. The device passed phases 1 and 2 in 33 participants. Mean discrepancies and standard deviations of the sphygmomanometer device were 1.8+/-6.6 mmHg for systolic blood pressure and 1.6+/-4.7 mmHg for diastolic blood pressure in the obese adult group. The device passed phases 1 and 2 in 33 participants in this group.

CONCLUSION

The Omron 637IT passed according to the International Protocol criteria and can be recommended for use in adults and obese adults.