Direct comparison of the reproducibility of in-office and self-measured home blood pressures

The long-term reproducibility of the white-coat effect on blood pressure as a continuous variable from the Ohasama Study

There is little information about the reproducibility of the white coat effect, which was treated as a continuous variable. To investigate a long-term interval reproducibility of the white-coat effect as a continuous variable. We selected 153 participants without antihypertensive treatment (men, 22.9%; age, 64.4 years) from the general population of Ohasama, Japan, to assess the repeatedly measured white-coat effect (the difference between blood pressures at the office and home) in a 4-year interval. The reproducibility was assessed by testing the intraclass correlation coefficient (two-way random effect model-single measures). The white-coat effect for systolic/diastolic blood pressure slightly decreased by 0.17/1.56 mmHg at the 4-year visit on average. The Bland-Altman plots showed no significant systemic error for the white-coat effects (P ≥ 0.24). The intraclass correlation coefficient (95% confidence interval) of the white-coat effect for systolic blood pressure, office systolic blood pressure, and home systolic blood pressure were 0.41 (0.27-0.53), 0.64 (0.52-0.74), and 0.74 (0.47-0.86), respectively. Change in the white-coat effect was mainly affected by a change in office blood pressure. Long-term reproducibility of the white-coat effect is limited in the general population without antihypertensive treatment. The change in the white-coat effect is mainly caused by office blood pressure variation.

Conventional office blood pressure measurements and unattended automated office blood pressure compared with home self-measurement and 24-h ambulatory blood pressure monitoring

OBJECTIVE

To assess whether automated office blood pressure (BP) (AOBP) measurement is a better method for measuring BP in the office than conventional techniques and an alternative to out-of-office BP measurements: home-self BP (HSBP) or ambulatory BP monitoring (ABPM).

METHODS

We conducted a cross-sectional study of 74 patients and compared AOBP with the conventional technique using a mercury sphygmomanometer and with both out-to-office BP measurements: HSBP of 7 days (three measurements in the morning, afternoon, and night) and daytime ABPM. In addition, we compared BP values obtained using HSBP and ABPM to determine their level of agreement. We used ANOVA to compare means, Bland-Altman, and intraclass correlation coefficients (ICC) for concordance.

RESULTS

BP values obtained by the two office methods were similar: conventional 147.2/85.0 mmHg and AOBP 146.0/85.5 mmHg ( P > 0.05) with good agreement (ICC 0.85). The mean SBP differences between AOBP and HSBP ( P < 0.001) and between AOBP and ABPM ( P < 0.001) were 8.6/13.0 mmHg with limits of agreement of -21.2 to 38.5 and -18.4 to 44.3 mmHg, respectively. The average SBP values obtained by HSBP were 4.3 mmHg higher than those obtained by ABPM ( P < 0.01).

CONCLUSION

Our study showed good agreement and concordance between the two office methods as well between the two out-to-office methods, although there was a significant difference in the mean SBP between the HSBP and ABPM. Moreover, AOBP was not comparable to either HSBP or ABPM; therefore, the estimation of out-to-office BP using AOBP is not supported.

Home blood pressure self-measurement: “Current situation and new perspectives”

The method typically used to diagnose and monitor hypertensive patients has been to measure blood pressure in the physician's surgery; however, it is a well-known fact that this approach poses certain drawbacks, such as observer bias, failure to detect an alert reaction in the clinic, etc., difficulties that affect its accuracy as a diagnostic method. In recent years, the varying international scientific societies have persistently recommended the use of blood pressure measurements outside the clinic (at home or in the outpatient setting), using validated automatic devices. Data from some studies suggest that if we rely solely on in-office measurements, approximately 15-20% of the time we may be wrong when making decisions, both in terms of diagnosis and patient follow-up. Home blood pressure measurements are a simple and very affordable method that has a similar reproducibility and prognostic value as ambulatory blood pressure monitoring, the availability of which is currently very limited. Moreover, ambulatory self-measurements have the significant benefit of being able to improve control of hypertensive individuals. Healthcare professionals and patients should be aware of the methodology of home blood pressure measurement, its usefulness and limitations.