Age-dependent changes in blood pressure over consecutive office measurements: impact on hypertension diagnosis and implications for international guidelines

Impact of within-visit systolic blood pressure change patterns on blood pressure classification: the Cardiovascular Risk in Young Finns Study

AIMS

Most international guidelines recommend that repeat blood pressure (BP) readings are required for BP classification. Two international guidelines diverge from this by recommending that no further BP measurements are required if the first clinic BP is below a hypertension threshold. The extent to which within-visit BP variability patterns change over time, and whether this could impact BP classification is unknown. We sought to examine this.

METHODS AND RESULTS

Data were from the Cardiovascular Risk in Young Finns Study, a prospective cohort study. Up to 2799 participants were followed from childhood (9-15 years) to adulthood (18-49 years) over up to six visits. Patterns of within-visit systolic BP (SBP) variability were defined as no-change, decrease, increase between consecutive readings (with 5 mmHg change thresholds). Classification of SBP (normal, high-normal, hypertension) using the first reading was compared with repeat readings. On average, SBP decreased with subsequent measures, but with major individual variability (no-change: 56.9-62.7%; decrease: 24.1-31.6%; increase: 11.5-16.8%). Patterns of SBP variability were broadly similar from childhood to adulthood, with the highest prevalence of an increase among participants categorized with normal SBP (12.6-20.3%). The highest prevalence of SBP reclassification occurred among participants with hypertension (28.9-45.3% reclassified as normal or high-normal). The prevalence of reclassification increased with the magnitude of change between readings.

CONCLUSION

There is a major individual variation of within-visit SBP change in childhood and adulthood and can influence BP classification. This highlights the importance of consistency among guidelines recommending that repeat BP measurements are needed for BP classification.

Within-visit SBP variability from childhood to adulthood and markers of cardiovascular end-organ damage in mid-life

BACKGROUND

Within-visit SBP variability is associated with age and SBP, but its long-term clinical significance is unknown. We examined the association between child, adult, and life-time within-visit SBP variability with markers of end-organ damage using data from a 31-year longitudinal study.

METHODS

Within-visit SBP variability was calculated as the standard deviation of three sitting SBP readings among up to 3010 participants aged 6-18 years (childhood) who were re-measured up to seven times to mid-adulthood. Markers of cardiovascular end-organ damage in adulthood were carotid intima--media thickness, brachial flow-mediated dilatation, carotid distensibility, pulse wave velocity, left ventricular mass index, carotid plaque, and coronary artery calcification.

RESULTS

The mean (standard deviation) cumulative within-visit SBP variability was 2.7 (1.5) mmHg in childhood, 3.9 (1.9) mmHg in adulthood and 3.7 (1.5) mmHg across the observed life-time. Childhood within-visit SBP variability was not correlated with its subsequent values measured from 3 to 31 years later. With adjustment for age, sex, cumulative SBP, BMI and serum lipids, neither child, adult, or life-time cumulative within-visit SBP variability associated with markers of cardiovascular end-organ damage. However, higher child, adult, and life-time cumulative SBP significantly associated with higher carotid intima--media thickness, higher pulse wave velocity, lower brachial flow-mediated dilatation, lower carotid distensibility in adulthood.

CONCLUSION

Within-visit SBP variability from childhood to adulthood does not provide additional predictive utility over SBP over the same period of the life course.

Utility of blood pressure measurements at an initial screening visit to identify Chinese children and adolescents with hypertension

The performance of different BP readings and their combinations at a visit to identify children and adolescents with pediatric hypertension remains controversial. We aimed to assess the utility of different blood pressure (BP) readings and their combinations obtained at the initial screening visit for identifying Chinese children and adolescents with hypertension. Participants were 7831 children and adolescents aged 6‐17 years measured as part of a cross‐sectional survey conducted in Jinan, China between September 2012 and November 2014. BP was measured three times at up to three visits. Elevated BP at the initial visit was defined as systolic BP and/or diastolic BP ≥ age‐ and sex‐specific 95th percentiles using the Chinese BP references for children and adolescents based on different BP readings and their combinations. Participants with elevated BP using (BP2+BP3)/2 across three visits were defined as having hypertension. Of the different readings or combinations examined, the mean of the last two readings at the initial visit had the best predictive utility for children and adolescents with hypertension (sensitivity: 100.0%; specificity: 86.9%; positive predictive value: 27.6%; negative predictive value: 100.0%). This was also reflected in the area under the curve being highest for the mean of the last two readings (0.93, 95% confidence interval: 0.93‐0.94) compared with any of the other readings or combinations (BP1, BP2, BP3, [BP1+BP2]/2, [BP1+BP3]/2, and [BP1+BP2+BP3]/3; all p < .001). Taking three measurements of BP and using the average of the last two readings at a screening visit may be optimal for the identification of hypertension in youth.

Blood pressure measurement protocol determines hypertension phenotypes in a Middle Eastern population

Clinic blood pressure (BP) measurement remains a crucial step in managing hypertension. While the number of measures recorded in different settings varies, with typically 1-3 measures, there has been no prior justification for the actual number of measures required. We investigated the pattern of BP variability over 5 consecutive automated readings (R1-R5) and the influence of patient characteristics on this pattern to identify the phenotype of hypertension in a Middle Eastern population. There were 1389 outpatients (51% men, 49% women), age range (18-87 y) who had 5 unattended automated consecutive BP measurements with one-minute intervals using the validated Datascope Mindray Passport V Monitor with the patient blinded from the results. Mean (±SEM) SBP for R1 (136.0 ± 2 mm Hg) was similar to R2 (136.2 ± 2 mm Hg). Thereafter SBP progressively declined till R5 by total of 5.5 mm Hg. The SBP decline was less (4.2 mm Hg) in older (>50 years) vs younger participants (8.1 mm Hg; P < .001) and was blunted in diabetic and hypertensive participants. Overall, 43% of participants had R2 > R1, and 24% additionally had R5 > R1. Age was a strong independent predictor of having both R2 > R1 and R5 > R1, as well as diabetes. Diastolic blood pressure (DBP) decreased by average 2.8 mm Hg from R1 to R5. Females had a 5-fold greater total decline in DBP vs males (P < .001). Using the mean of 5 BP measures resulted in fewer participants being classified as hypertensive (36% of the population) compared to using one measurement (46%), or established BP guidelines which use different combinations of R1-R3 (37%-42%). Our findings in a Middle Eastern population highlight the importance of the BP measurement protocol in combination with patient characteristics in determining whether a patient is diagnosed with hypertension. Protocols that rely on different combinations of only 3 measures (R1-3) will classify more participants as hypertensive, compared to using 5 measures or disregarding a high R2.

Multiple office blood pressure measurement: a novel approach to overcome the weak cornerstone of blood pressure measurement in children. Data from the SPA project

BACKGROUND

This contribution aims to report and analyze a novel approach for office blood pressure measurement in children.

METHODS

Healthy children 5 to 8 years of age were eligible. After 5 minutes rest, 10 unattended blood pressure readings were taken at 3-minute intervals using a validated automated oscillometric device. After discarding outlier values (< 5th or > 95th percentile of the recorded values), the coefficient of variation and the mean of the 10 readings were calculated. The single readings #1 to #10 were compared with this elaborated average of the 10 measurements.

RESULTS

Two hundred eighty-one healthy, non-obese children (137 females, 49%), median age 5.7 (IQR 5.3-6.1) years, were analyzed. The median coefficients of variation were 7% (IQR 5-9) for systolic and 4% (IQR 3-6) for diastolic blood pressure. The first 3 measurements were significantly different from the average, while the readings #4 to #10 were not. Based on the average, only nine subjects had a systolic or diastolic blood pressure > 90th centile (n = 3 > 95th percentile).

CONCLUSIONS

Although most guidelines advise three blood pressure readings, these findings suggest that in children, office blood pressure measurement might be improved by including ten measurements. In situations of time constraints, the fourth blood pressure reading might be used as a reliable approximation.

Misclassification of blood pressure of Vietnamese adults when only a single measurement is used

A single clinic measurement of blood pressure (BP) may be common in low- and middle-income countries because of limited medical resources. This study aimed to examine the potential misclassification error when only one BP measurement is used. Participants (n = 14,706, 53.5% females) aged 25-64 years were selected by multistage stratified cluster sampling from eight provinces, each representing one of the eight geographical regions of Vietnam. Measurements were made using the World Health Organization STEPS protocols. Data were analyzed using complex survey methods. For systolic BP, 62.7% had a higher first reading whereas 30.0% had a lower first reading, and 27.3% had a reduction of at least 5 mmHg whereas 9.6% had an increase of at least 5 mmHg. Irrespective of direction of change, increased variability in BP was associated with greater age, urban living, greater body size and fatness, reduced physical activity levels, elevated glucose, and raised total cholesterol. These measurement variations would lead to substantial misclassification in diagnosis of hypertension based on a single reading because almost 20% of subjects would receive a different diagnosis based on the mean of two readings.

Reliability of single office blood pressure measurements

Objectives

Standard operating procedures for office blood pressure measurement (OBPM) vary greatly between guidelines and studies. We aimed to compare the difference between a single OBPM and the mean of the three following measurements. Further, we studied how many patients with possible hypertension may be missed due to short-term masked hypertension (STMH) and how many might be overdiagnosed due to short-term white coat hypertension (STWCH).

Design and setting

In this cross-sectional, single-centre trial, 1000 adult subjects were enrolled. After 5 min of rest, four sequential standard OBPMs were performed at 2 min intervals in a quiet room in sitting position. We compared the first (fBPM) to the mean of the second to fourth measurement (mBPM). STMH was defined as fBPM <140 mm Hg systolic and <90 mm Hg diastolic and mBPM systolic ≥140 mm Hg or diastolic ≥90 mm Hg. STWCH was defined as fBPM systolic ≥140 mm Hg or diastolic ≥90 mm Hg and mBPM <140 mm Hg systolic and <90 mm Hg diastolic.

Results

Complete measurements were available in 802 subjects. Between fBPM and mBPM, 662 (82.5%), 441 (55%) and 208 (25.9%) subjects showed a difference in systolic and 531 (66.2%), 247 (30.8%) and 51 (6.4%) in diastolic blood pressure (BP) values of >2 mm Hg, >5 mm Hg and >10 mm Hg, respectively. In 3.4% of initially normotensives STMH and in 34.3% of initially hypertensives, STWCH was apparent.

Conclusions

There are significant differences between a single OBPM and the mean of consecutive BP measurements. Our study provides evidence that a single OBPM should not be the preferred method and should be discouraged in future guidelines.

Trial registration number

NCT02552030;Results.

Influence of blood pressure level and age on within-visit blood pressure variability in children and adolescents

Blood pressure (BP) is variable in children and this could affect BP assessment, but the magnitude of within-visit BP variability (BPV) over consecutive measurements has never been investigated. This study aimed to determine the direction and magnitude of, and factors affecting, within-visit BPV in children and adolescents. BP was recorded among 3047 children (aged 12 years [95%CI 12, 13], males 52%) from the 2011-2013 Australian Health Survey. BPV was defined as the absolute difference (∆SBP_ABS) between the first (SBP1) and second systolic BP (SBP2) and the overall variability in three measures when available (SBPV). On average, ∆SBP_ABS was 6.7 mmHg (95%CI 6.3, 7.0) and SBPV was 8.2% (95%CI 7.8, 8.6). ∆SBP_ABS was greater with higher BP levels but lower with older age. From first to second measurements, SBP decreased in 58% (95%CI 56, 60), did not change in 10% (95%CI 9, 12), and increased in 32% (95%CI 29, 34) of the population.

CONCLUSIONS

BP is highly variable in children and adolescents, with the magnitude of variability being associated with both age and BP level. SBP increases on repeat measurement in a substantial proportion of the population. The optimal protocol of BP assessment to address this increased BPV needs to be determined. What is Known: • Diagnosis of elevated blood pressure (BP) is based on strict probabilistic criteria, the difference between the 90th (pre-hypertension) and 95th (hypertension) percentiles only being 3-4 mmHg. • BP variability could affect BP classification among children and adolescents. What is New: • The magnitude of BP change among children and adolescents is highly affected by BP level and age. • BP does not always drop on consecutive measurements, and evidence-based BP assessment protocols should be established to avoid misdiagnosis of hypertension.