The occurrence of the alerting response is independent of the method of blood pressure measurement in hypertensive patients

Comparison of blood pressure measurements obtained in the home setting: analysis of the Health Measures at Home Study

BACKGROUND

Automated blood pressure (BP) devices have been used in the home for self-management purposes and are increasingly being used in population-based research. Although these devices are convenient and affordable and may be used by inexperienced lay personnel, the potential impact of an examiner's skill level on the results needs to be evaluated quantitatively. The aim of this study was to compare BP measurements obtained in a home setting by personnel with healthcare experience with those obtained by personnel without healthcare experience. In addition, the percent agreement in high blood pressure (HBP) classification between the home BP measurement by the field interviewer (FI) and measurements obtained in a standardized environment was examined.

METHODS

The Health Measures at Home Study was a pilot study carried out among 128 adult participants recruited from the National Health and Nutrition Examination Survey. The Health Measures at Home Study provided the opportunity to compare the BP values obtained with an automated device in a home setting by both experienced health technicians (HTs) with those obtained by FIs who had no healthcare experience. Differences between measurements obtained by the HT and measurements obtained by the FI were assessed using paired t-tests, Pearson's correlations, and Bland-Altman plots. Percent agreement and κ-statistics were used to assess agreement in HBP classification between examiners in the home. Measurements obtained by the FI were also compared with those obtained in the National Health and Nutrition Examination Survey mobile exam center (MEC) by a physician using percent agreement and κ-statistics.

RESULTS

There was a high correlation in both systolic blood pressure (SBP; r=0.903) and diastolic blood pressure (DBP; r=0.894) between measurements obtained by HTs and those obtained by FIs. The mean SBP and DBP obtained by the FIs (SBP, 119.0±14.4 mmHg; DBP, 71.9±9.8 mmHg) were significantly higher than the HT measurements (SBP, 117.0±12.7 mmHg; DBP, 69.9.9±9.2 mmHg). In the home, the FI classified 11.7% as having HBP, whereas the HT classified 7.0%. The percent of individuals classified as having HBP by the physician in the MEC was 10.2% of the participants.

CONCLUSION

Operationally, FIs could take BP measurements in the home; however, there were some differences between measurements obtained by the FI and HT. The absolute difference between measurements obtained by the FI and those obtained by the HT in the home showed that measurements obtained by the FI tended to be higher than the HT, but the magnitude of these differences was less than 5 mmHg. The HT classified 7.0% of HBP whereas the FI classified 11.7% of HBP. Similarly, the FI and the MEC physician classified a different percent of individuals with HBP. Further investigation is warranted to determine the cause of these small but significant absolute differences between measurements obtained by the FI and HT.

A new automatic blood pressure kit auscultates for accurate reading with a smartphone: A diagnostic accuracy study

The widely used oscillometric automated blood pressure (BP) monitor was continuously questioned on its accuracy. A novel BP kit named Accutension which adopted Korotkoff auscultation method was then devised. Accutension worked with a miniature microphone, a pressure sensor, and a smartphone. The BP values were automatically displayed on the smartphone screen through the installed App. Data recorded in the phone could be played back and reconfirmed after measurement. They could also be uploaded and saved to the iCloud. The accuracy and consistency of this novel electronic auscultatory sphygmomanometer was preliminarily verified here. Thirty-two subjects were included and 82 qualified readings were obtained. The mean differences ± SD for systolic and diastolic BP readings between Accutension and mercury sphygmomanometer were 0.87 ± 2.86 and -0.94 ± 2.93 mm Hg. Agreements between Accutension and mercury sphygmomanometer were highly significant for systolic (ICC = 0.993, 95% confidence interval (CI): 0.989-0.995) and diastolic (ICC = 0.987, 95% CI: 0.979-0.991). In conclusion, Accutension worked accurately based on our pilot study data. The difference was acceptable. ICC and Bland-Altman plot charts showed good agreements with manual measurements. Systolic readings of Accutension were slightly higher than those of manual measurement, while diastolic readings were slightly lower. One possible reason was that Accutension captured the first and the last korotkoff sound more sensitively than human ear during manual measurement and avoided sound missing, so that it might be more accurate than traditional mercury sphygmomanometer. By documenting and analyzing of variant tendency of BP values, Accutension helps management of hypertension and therefore contributes to the mobile heath service.

Aldosterone Synthase Promoter Polymorphism and Cardiovascular Phenotypes in a Large, Multiethnic Population-Based Study

BACKGROUND

A single-nucleotide polymorphism in the aldosterone synthase gene (CYP11B2) promoter [-344C/T, rs1799998] has been reported to associate with cardiovascular phenotypes.

METHODS

The Dallas Heart Study is a large, multiethnic cohort with a high prevalence of hypertension. We genotyped 3452 Dallas Heart Study participants for -344C/T. Generalized linear models were used to assess whether variation at -344C/T associated with plasma aldosterone concentration (PAC), systolic and diastolic blood pressure (SBP and DBP), plasma glucose (in persons with no diabetes), HOMA IR (Homeostasis Model Assessment as an Index of Insulin Resistance), and left ventricular (LV) mass indexed to height. Systolic blood pressure and DBP were significantly higher in blacks compared with whites (P < 0.001 for SBP and for DBP) and Hispanics (P < 0.001 for SBP and for DBP). Log-transformed body mass index was also significantly higher in blacks compared with whites (P < 0.001), but not Hispanics (P = 0.10). Log-transformed PAC was higher in whites compared with blacks (P < 0.001), but did not differ significantly in whites compared with Hispanics (P = 0.73). In univariate and multivariable analysis, -344C/T was not significantly associated with PAC within any ethnicity. In univariate and multivariable analysis, -344C/T was not associated with SBP or DBP within any ethnicity. After adjustment for multiple testing, univariate and multivariable analyses revealed no association between -344C/T and plasma glucose in patients with no diabetes, HOMA IR, or LV mass indexed to height.

CONCLUSIONS

We were unable to reproduce previously reported associations between -344C/T and PAC, blood pressure, plasma glucose, or LV mass. Methodological differences might explain the differences between our findings and those previously reported.

Doctors record higher blood pressures than nurses: systematic review and meta-analysis

BACKGROUND

The magnitude of the 'white coat effect', the alerting rise in blood pressure, is greater for doctors than nurses. This could bias interpretation of studies on nurse-led care in hypertension, and risks overestimating or overtreating high blood pressure by doctors in clinical practice.

AIM

To quantify differences between blood pressure measurements made by doctors and nurses.

DESIGN AND SETTING

Systematic review and meta-analysis using searches of MEDLINE, CENTRAL, CINAHL, Embase, journal collections, and conference abstracts.

METHOD

Studies in adults reporting mean blood pressures measured by doctors and nurses at the same visit were selected, and mean blood pressures extracted, by two reviewers. Study risk of bias was assessed using modified Cochrane criteria. Outcomes were pooled across studies using random effects meta-analysis.

RESULTS

In total, 15 studies (11 hypertensive; four mixed hypertensive and normotensive populations) were included from 1899 unique citations. Compared with doctors' measurements, nurse-measured blood pressures were lower (weighted mean differences: systolic -7.0 [95% confidence interval {CI} = -4.7 to -9.2] mmHg, diastolic -3.8 [95% CI = -2.2 to -5.4] mmHg). For studies at low risk of bias, differences were lower: systolic -4.6 (95% CI = -1.9 to -7.3) mmHg; diastolic -1.7 (95% CI = -0.1 to -3.2) mmHg. White coat hypertension was diagnosed more frequently based on doctors' than on nurses' readings: relative risk 1.6 (95% CI =1.2 to 2.1).

CONCLUSIONS

The white coat effect is smaller for blood pressure measurements made by nurses than by doctors. This systematic difference has implications for hypertension diagnosis and management. Caution is required in pooling data from studies using both nurse- and doctor-measured blood pressures.