Is masked hypertension an artefact due to the blood pressure measurement method and threshold effects?

From results of office and home measurements of blood pressure (BP), patients can be classified as "hypertensive (HT)", "normotensive (NT)", "office hypertensive (OH)" or "masked hypertensive (MH)" by crossing the classifications obtained from each method. It seems that 9 to 20% of patients could be MH with a prognosis close to HT (SHEAF study). OBJECTIVES: To test the hypothesis that at least one part of the prevalence of MH would be an artefact due to the difference between the methods of measurements (shygmomanometer vs semi-automatic device) and/or due to different definitions of office hypertension (OHT). To determine the impact of different definitions of OHT on the prevalence of MH. METHODS: During the course of a phase IV study, BP was measured with the same semi-automatic device (OMRON 705CP) both at doctor's office (3 measurements at 1-minute intervals) and at home, by the patient himself (3 measurements in the morning and in the evening at 1-minute intervals over the 7 days before the visit). Following definitions were used: Office HT: SBP > or =140 mmHg, DBP > or =90 mmHg, SBP > or =140 mmHg or DBP > or =90 mmHg; Home HT: SBP > or =135 mmHg, DBP> or =85 mmHg, SBP > or =135 mmHg or DBP > or =85 mmHg. Another definition of office HT was used SBP > or =135 mmHg, DBP > or =85 mmHg SBP > or =135 mmHg or DBP > or =85 mmHg. RESULTS: 575 patients were analysed. Results from the two methods of measurements are closed but significantly different (difference for SBP: 3.2 +/- 16.5 mmHg; p < 0.0001; difference for DBP: 1.4 +/- 10.3 mmHg; p = 0.002)     

Which is the correct term for blood pressure measurements taken at home?

The terms 'self-blood pressure' and 'home blood pressure' are being used to describe measurements of blood pressure taken by the patients at home. However, home measurements are not always self-measurements, because these are often taken by the patients' relatives. There is little evidence on the effect of self-measurement on the level of blood pressure taken using automated electronic devices. In regard to clinic blood pressure, two studies using automated devices found no difference between measurements taken by physicians or patients themselves, irrespective of whether self-measurements were taken in the presence or the absence of the physician. In regard to home blood pressure, one randomized crossover trial showed no difference between home measurements taken by the patients themselves or their relatives using fully automated devices. On the other hand, many studies have consistently shown home blood pressure to be lower than clinic pressure. Taken together these data suggest that self-measurement has no effect on the level of blood pressure, either in the clinic, or at home. The lower level of home in comparison to clinic blood pressure seems to be exclusively attributed to the effect of the different setting, rather than the person who is taking measurements. Therefore the term 'self blood pressure' seems to be a misnomer, whereas the term 'home blood pressure' represents a more appropriate term for home measurements taken by patients or their relatives.     

Self-measurement of blood pressure at home: is it reliable?

Self-measurement of blood pressure (BP) at home is more common than 10 years ago and encouraged by current guidelines to increase patient adherence to treatment and reach the goal of target BP. The aims of this study are to evaluate the accuracy of home sphygmomanometers and to investigate behavior/knowledge of the sphygmomanometer owners. A campaign was planned to determine the accuracy of home sphygmomanometers in 2006. Seven hundred and twenty-three home sphygmomanometers were brought by individuals to the University Hospital Hypertension Clinic within 1 year and 693 (96%) of the devices were in adequate working condition and suitable for analysis. Four hundred and thirty-nine (63%) of the sphygmomanometers were automatic. Four hundred and eleven (59.3%) of the 693 sphygmomanometer were inaccurate. About 80% (256/320) of the wrist devices were inaccurate. Most studies evaluating the accuracy of sphygmomanometers are conducted in hospital or primary care settings; studies investigating home sphygmomanometers are rare. High frequency of inaccurate home devices is a major public health problem. In conclusion, inaccurate devices have been used in home BP measurements frequently and frequency of device-related errors can be decreased by awareness and training of the patients. Physicians and healthcare providers should advise the patients to check the accuracy of their home sphygmomanometers regularly.     

How do we use ambulatory measurement of blood pressure in the management of hypertension?

We have explored the use and interpretation of ambulatory blood pressure monitoring (ABPM) among clinicians at an Edinburgh Cardiovascular Risk Clinic and among a group of international experts in blood pressure monitoring. Locally, we were able to demonstrate major discrepancies in management advice between doctors and nurses. Although all of the international experts used ABPM regularly, they did not agree on thresholds levels for treatment or target BP. This gives food for thought as we consider how to advise internists and primary care physicians on the use and interpretation of ABPM.     

Which measurement of home blood pressure should be used for clinical evaluation when multiple measurements are made?

OBJECTIVE: We evaluated which home blood pressure (BP) measurement was most useful in clinical evaluation when we measured it three times per sitting. METHODS: Home BP measurements in the morning and evening were performed for 7 days in 572 volunteers (384 men, 188 women, mean age 41.2 years) in 2002 (period 1) and 2003 (period 2). Five sets of measurements were analyzed: A, mean of the first; B, mean of the second; C, mean of the first and second; D, mean of the second and third; and E, mean of all measurements. By analyzing BP in five sets in both periods, their reproducibility was examined. RESULTS: For all five sets of measurements, little difference was found when BP readings were compared between both periods [the differences were -0.6 +/- 6.7 to -0.4 +/- 7.0 mmHg for morning systolic BP (SBP), 0 +/- 4.9 to 0.3 +/- 5.0 mmHg for morning diastolic BP (DBP), -0.1 +/- 7.1 to 0.1 +/- 7.0 mmHg for evening SBP, and 0.1 +/- 5.3 to 0.4 +/- 5.4 mmHg for evening DBP]. Furthermore, BP readings between both periods correlated well; the correlation coefficients were 0.90-0.92 for morning BP and 0.86-0.89 for evening BP. In addition, the concordance rates of three BP categories (normotension, borderline and hypertension) were excellent using morning home BP (kappa coefficient 0.64-0.68) in all five sets, and higher than those using evening home BP (0.52-0.57). CONCLUSIONS: This study has shown that even one measurement on each occasion is as useful as several measurements when 7 consecutive days of home BP measurements are used for clinical evaluation.     

How should we measure blood pressure? Implications of the fourth blood pressure measurement in office blood pressure

According to the European Hypertension Guidelines regarding office blood pressure measurements (OBPMs), the mean between second/third or third/fourth OBPM should be taken if the first two readings differ by ≤10 or >10 mmHg, respectively. Our aim was to explore the value of the fourth OBPM and determine whether a simplified OBPM procedure is feasible without loss of quality. In this cross‐sectional study, four standard OBPMs were taken. The mean of the second/third OBPM (S2S3/D2D3) and third/fourth OBPM (S3S4/D3D4) for systolic/diastolic values was calculated. Correlation, agreement, and differences regarding BP classification were explored for the entire cohort and subsets with a difference between the first/second OBPM (S1S2/D1D2) ≤10 and >10 mmHg. Overall (n = 802) and for the subsets with an S1S2 (n = 596) and D1D2 (n = 742) difference ≤10 mmHg, S3S4/D3D4 was in median 0.5 mmHg lower than S2S3/D2D3, respectively (p < .0005 for all). In participants with an S1S2 (n = 206) and D1D2 (n = 60) difference >10 mmHg, S3S4/D3D4 differed numerically from S2S3/D2D3, respectively (p > .1 for all). Overall and for all subsets with an S1S2/D1D2 difference ≤10/>10 mmHg, less subjects were numerically classified as hypertensive with S3S4/D3D4 than with S2S3/D2D3 (p > .04), but BP reclassification occurred in both directions in 1.0%‐10.0%, depending on the cohort. In conclusion, the third/fourth OBPM results in lower BP values than the second/third measurement, regardless of the difference between first/second OBPM, whereby BP reclassifications occurred in both directions. Therefore, the cutoff of >10 versus ≤10mmHg difference between first/second OBPM to implement a fourth BPM harbors the risk of distorted results. We therefore recommend using the second/third BPM for standardized OBPM. Trial registration: Registered on clinicaltrials.gov (NCT02552030).     

Bell or diaphragm in the measurement of blood pressure?

BACKGROUND: International guidelines have given diverse recommendations as to which side of the stethoscope should be used in the measurement of blood pressure. OBJECTIVE: To determine if there is any difference between the bell and the diaphragm sides of the ordinary acoustic stethoscope in the measurement of blood pressure. DESIGN AND METHODS: We compared, in random order, the bell and the diaphragm side of the ordinary acoustic stethoscope and also the effect of low- and high-frequency amplification with an electronic stethoscope in the measurement of blood pressure, in 250 adults. SETTING: Department of Medicine, Turku University Central Hospital. RESULTS: No statistically significant difference was seen between the bell side and the diaphragm side of the acoustic stethoscope, either in systolic blood pressure (SBP; mean +/- SD 129.5 +/- 21.7 and 129.4 +/- 20.8 mmHg, respectively) or diastolic blood pressure (DBP; 77.0 +/- 12.0 and 77.1 +/- 12.0 mmHg, respectively). Both the low-frequency (130.7 +/- 22.5 mmHg) and the high-frequency (131 +/- 22.2 mmHg) amplification of systolic Korotkoff sounds yielded significantly greater values of SBP than were measured either with the bell (P = 0.008 compared with low frequency, P = 0.0005 compared with high frequency) or the diaphragm (P = 0.004 compared with low frequency, P = 0.0001 compared with high frequency). Low-frequency amplification of DBP (76.4 +/- 12.3 mmHg) yielded values significantly lower than those measured with the bell (P = 0.04) or the diaphragm (P = 0.01). Values from high-frequency amplification of DBP (77.2 +/- 12.3 mmHg) did not differ significantly from those measured with the acoustic stethoscope. CONCLUSIONS: Both sides of the acoustic stethoscope give similar results in the measurement of office blood pressure and either side can be used in the reliable measurement of blood pressure.     

Hypertension and the cardiometabolic syndrome--is it the blood pressure lowering or the blood pressure medication that is important?

Elevated blood pressure and the cardiometabolic syndrome are often difficult clinical challenges specifically related to fusing appropriate lifestyle modifications and antihypertensive agents. This case illustrates some of the factors clinicians have utilized in approaching patients with this common but challenging clinical situation.