Blood pressure-to-height ratio as a screening measure for identifying children with hypertension

Defining childhood hypertension: is it too complicated? An evaluation of the potential impact of different approaches in an Australian paediatric population

OBJECTIVES

Current American Academy of Pediatrics (AAP) and European Society of Hypertension (ESH) thresholds defining hypertension in children use blood pressure (BP) normalised to age, sex and height. However, scare data exists regarding the relative importance of these variables to accurately model the 95th quantile of BP. We hypothesised that height alone may fit the population data equally well compared to more complex definitions. We also compare the potential impact of various thresholds for defining hypertension in an Australian population.

METHODS

Longitudinal data from the Raine Study were used, with 2248 participants contributing 7479 valid BP values across the 3/5/10/14/17-year study visits. BP was measured after 5 min rest, ≥3 times at each visit, using a Dinamap device. Quantile regression was used to predict the 95th percentile of BP, with nonlinear modelling of covariates through restricted cubic spline terms.

RESULTS

At a single visit, 6-16% of young children exceeded the ESH threshold and 12-23% the AAP threshold. The transition to fixed thresholds (≥13 years AAP, ≥16 years ESH), increased the number of males (AAP only) and reduced the number of females considered hypertensive. A quantile regression model constructed with Raine Study data using height-only as the explanatory variable better predicted BP than the respective model using age-only (or a combination of the two).

CONCLUSIONS

There may be large differences in the prevalence of hypertension according to AAP and ESH criteria, with a marked sex-discrepancy emerging from the point of fixed threshold application in adolescence. It may not be necessary to normalise BP by both age and height, the latter being a better predictor of childhood BP. Simpler methods may be preferable in clinical practice but require validation against clinical outcomes.

Blood pressure standards for pre-school children in Saudi Arabia

The prevalence of hypertension (HTN) in children is increasing. Early detection of HTN in childhood may prevent the occurrence of complications in adult age. Blood pressure (BP) varies between populations according to ethnic and environmental factors. Based on these variations, reference norms developed for one particular population may not be applicable to others. Thus, this study aimed to provide age-, gender-, and height-related BP reference standards using oscillometric techniques for pre-school children in Saudi Arabia. A sub-sample of preschool children aged from 2 to 6 years was selected by multi-stage probability sampling of Saudi population. The samples represented Saudi children from the whole country. Data were collected through a house-to-house survey of all selected households in all 13 regions in the country. Oscillometric devices were used to measure the BP. Data were analyzed to study the distribution pattern of systolic (SBP) and diastolic BP (DBP) and to develop reference values based on age, gender, and height. The values for each age and height percentile were compared with the recent (2017) values of the North American children. A total of 2553 Saudi Arabian children (1299 boys and 1254 girls) aged 2-6 years with complete data on age, gender, height, SBP, and DBP were considered for analysis. Values for SBP and DBP were significantly higher in Saudi children than in the North American children. This study adds evidence to the BP variations between populations with influences such as genetic and environmental factors. The need of every population to define its normal BP standards is essential to avoid unnecessary investigations and anxiety in patients and their parents.

Using height-corrected definition of metabolic syndrome in children and adolescents

Metabolic syndrome (MS) is common among children and adolescents. Age- and gender-specific references or age-, gender- and height-specific references were used in pediatric MS definitions. More recently, an increasing number of studies documented that the ratio of waist circumference (WC) to height (WHtR) and blood pressure to height (BPHR) were easy anthropometric indexes for detection of obesity and hypertension in children and adolescents. For these reasons, height-corrected MS definition was proposed. WHtR and BPHR were used as alternatives to WC and BP in the definition of MS. In the present review, we discuss the possibility of the height-corrected MS definition for identifying MS in children.

Height-Based Equations Can Improve the Diagnosis of Elevated Blood Pressure in Children

Background

High blood pressure (BP) is usually underdiagnosed in children and adolescents, particularly due to its complex diagnosis process. This study describes novel height-based equations for the detection of BP disorders (BP > 90th percentile) and compares the accuracy of this approach with previously described screening methods to identify BP disorders.

Methods

Height-based equations were built using the 90th percentile values for systolic and diastolic BP and respective height values from the current guideline of high-BP management in children. This guideline was also used as the gold standard method for identification of BP disorders. The equations were tested in Brazilian (n = 2,936) and American (n = 6,541) populations of children with 8-13 years old.

Results

The obtained equations were 70 + 0.3 × height (in cm) for systolic BP and 35 + 0.25 × height (in cm) for diastolic BP. The new equations presented sensitivity and negative predictive value of near 100% and specificity > 91% and showed higher specificity and positive predictive value when compared with other screening tools. Importantly, height-based equations had greater agreement (kappa coefficient = 0.75-0.81) with the gold standard method than the other methods (kappa coefficient = 0.53-0.73). Further analysis showed that alternative height-based equations designed to identify hypertension (BP ≥ 95th percentile) also showed superior performance (kappa coefficient = 0.89-0.92) compared with other screening methods (kappa coefficient = 0.43-0.85).

Conclusions

These findings suggest that the use of height-based equations may be a simple and feasible approach to improve the detection of high BP in the pediatric population.

Sonographic evaluation of renovascular hypertension in the pediatric population: State-of-the-art

Hypertension in children affects 2-5% of the pediatric population. Identifying secondary causes of hypertension is crucial, as some of these entities may be treatable. Renovascular hypertension accounts for 5-10% of the secondary causes of hypertension in children and is mainly related to fibromuscular dysplasia and neurofibromatosis type 1. Ultrasonographic evaluation of the kidneys, including Doppler interrogation, is the recommended primary screening tool. A comprehensive study of the upper abdomen and retroperitoneum allows for identification of additional underlying etiologies. The purpose of this review is to emphasize the different causes of renovascular hypertension in children one can diagnose during the initial ultrasonographic evaluation. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 45:282-292, 2017.

Performance of User-Friendly Screening Tools for Elevated Blood Pressure in Children

CONTEXT

Hypertension is frequently undiagnosed in children. Several methods have been developed to simplify screening for elevated blood pressure (BP) in children.

OBJECTIVE

to assess the performance of different screening tools in identifying elevated BP in the pediatric population.

DATA SOURCES

Data sources such as PubMed, Embase, Web of Science, Cochrane, and Scopus were searched up to March 2016.

STUDY SELECTION

Studies providing measures of diagnostic performance of screening tools and that used age-, sex-, and height-specific BP percentile as the reference standard were included.

DATA EXTRACTION

Data regarding the population, screening tools used to define elevated BP, and diagnostic criteria of BP were extracted. Available data on true-positive, false-positive, true-negative, and false-negative results were also extracted to construct a 2 × 2 contingency table.

RESULTS

A total of 16 eligible studies that evaluated 366 321 children aged 3 to 18 years were included in the meta-analysis. Nine screening tools were included in this study, in which the BP-to-height ratio, the modified BP-to-height ratio, and tables based on age categories had the highest sensitivities (97-98%) but moderate specificities (71-89%).

LIMITATIONS

Limitations included that BP measurements in most studies were based on 1 visit only and there was heterogeneity between the studies.

CONCLUSIONS

Several user-friendly screening tools could improve the screening of elevated BP in the pediatric population.

Suitability of blood-pressure-to-height ratio as the criterion for high blood pressure in children in an environmental study

BACKGROUND

Blood-pressure-to-height ratio is considered a simple, accurate, inexpensive and non-age-dependent index for screening high blood pressure in a clinical setting, but its suitability in epidemiological surveys was not taken into consideration. The aim of this study was to test the suitability of blood-pressure-to-height ratio against blood pressure for age percentiles for the identification of high blood pressure in an environmental study.

METHODS

The sample consisted of 2195 children, aged 3 to 15 years, whose blood pressure was measured as part of an environmental study in Belgrade, Serbia. High blood pressure was estimated using percentiles (gold standard) and blood-pressure-to-height ratios for systolic and diastolic pressures separately (proposed criterion). The optimal cut-offs of the blood-pressure-to-height ratio (BPHR) were selected based on Youden's index (sensitivity + specificity - 1) calculated from the receiver operator characteristic curve analysis.

RESULTS

The proposed criterion identified five times more cases of high blood pressure in the investigated children of all age groups in comparison to the gold standard. The optimal cut-off values were selected based on the sensitivity and specificity values by age groups and gender.

CONCLUSION

Blood-pressure-to-height ratio can be a reliable criterion for the estimation of high blood pressure in epidemiological studies. This is the first study on the applicability of blood-pressure-to-height ratio in Serbian children, but it may not be easily generalized to other populations due to small sample size across the examined age groups and potential diversities in risk factors for high blood pressure. Applied in epidemiological studies, BPHR would help researchers estimate the role of certain environmental factors on blood pressure in children.

Blood pressure-to-height ratio as a screening indicator of elevated blood pressure among children and adolescents in Chongqing, China

We aimed to evaluate the performance of blood pressure-to-height ratio (BPHR) and establish their optimal thresholds for elevated blood pressure (BP) among children aged 6 to 17 years in Chongqing, China. Data were collected from 11 029 children and adolescents aged 6-17 years in 12 schools in Chongqing according to multistage stratified cluster sampling method. The gold standard for elevated BP was defined as systolic blood pressure (SBP) and/or diastolic blood pressure (DBP) ⩾95th percentile for gender, age and height. The diagnostic performance of systolic BPHR (SBPHR) and diastolic BPHR (DBPHR) to screen for elevated BP was evaluated through receiver-operating characteristic curves (including the area under the curve (AUC) and its 95% confidence interval, sensitivity and specificity). The prevalence of elevated BP in children and adolescents in Chongqing was 10.36% by SBP and/or DBP ⩾95th percentile for gender, age and height. The optimal thresholds of SBPHR/DBPHR for identifying elevated BP were 0.86/0.58 for boys and 0.85/0.57 for girls among children aged 6 to 8 years, 0.81/0.53 for boys and 0.80/0.52 for girls among children aged 9 to 11 years and 0.71/0.45 for boys and 0.72/0.47 for girls among adolescents aged 12-17 years, respectively. Across gender and the specified age groups, AUC ranged from 0.82 to 0.88, sensitivity were above 0.94 and the specificities were over 0.7. The positive predictive values ranged from 0.30 to 0.38 and the negative predictive values were ⩾0.99. BPHR, with uniform values across broad age groups (6-8, 9-11 and 12-17 years) for boys and for girls is a simple indicator to screen elevated BP in children and adolescents in Chongqing.

Performance of blood pressure-to-height ratio as a screening tool for elevated blood pressure in pediatric population: a systematic meta-analysis

The aim of this study was to assess the performance of the blood pressure-to-height ratio (BPHR) for screening elevated blood pressure (BP) in children and adolescents using a meta-analysis of eligible published studies. We retrieved studies that investigated the performance of the BPHR for identifying elevated BP from Pubmed and other databases. We performed meta-analyses by subgroups of sex, age and ethnicity using a fixed or random effect model based on whether there was between-study heterogeneity. A total of 13 publications including 262 830 children and adolescents aged 6-18 years on BPHR and a total of three publications including 95 343 children on the modified BPHR were included in this meta-analysis. The summary results suggested that BPHR performed well to identify pre-high BP and high BP for children aged 6-11 years and adolescents aged 12-18 years. The performance of BPHR was perfect for identifying severe high BP in adolescents aged 12-18 years. However, the modified BPHR did not improve accuracy for screening high BP in children aged 6-12 years. In summary, BPHR performed well for identifying elevated BP in children and adolescents, independently of sex, age and ethnicity group. In addition, the modified BPHR performed similarly with BPHR for screening high BP in childhood.

Accuracy of Blood Pressure-to-Height Ratio to Define Elevated Blood Pressure in Children and Adolescents: The CASPIAN-IV Study

The aim of this study was to propose a simple practical diagnostic criterion for pre-hypertension (pre-HTN) and hypertension (HTN) in the pediatric age group. This study was conducted on a nationally representative sample of 14,880 students, aged 6-18 years. HTN and pre-HTN were defined as systolic blood pressure (SBP) and/or diastolic blood pressure (DBP) ≥ 95 and 90-95th percentile for age, gender, and height, respectively. By using the area under the curve (AUC) of the receiver operator characteristic curves, we estimated the diagnostic accuracy of two indexes of SBP-to-height ratio (SBPHR) and DBP-to-height (DBPHR) to define pre-HTN and HTN. Overall, SBPHR performed relatively well in classifying subjects to HTN (AUC 0.80-0.85) and pre-HTN (AUC 0.84-0.90). Likewise, DBPHR performed relatively well in classifying subjects to HTN (AUC 0.90-0.97) and pre-HTN (AUC 0.70-0.83). Two indexes of SBPHR and DBPHR are considered as valid, simple, inexpensive, and accurate tools to diagnose pre-HTN and HTN in pediatric age group.

Strengths and limitations of current pediatric blood pressure nomograms: a global overview with a special emphasis on regional differences in neonates and infants

The availability of robust nomograms is essential for the correct evaluation of blood pressure (BP) values in children. A literature search was conducted by accessing the National Library of Medicine by using the keywords BP, pediatric and reference values/nomograms. A total of 43 studies that evaluated pediatric BP nomograms were included in this review. Despite the accuracy of the latest studies, many numerical and methodological limitations still remain. The numerical limitations include the paucity of data for neonates/infants and for some geographic areas (Africa/South America/East Europe/Asia) and ethnicities. Furthermore, the data on ambulatory BP and response to exercise are extremely limited, and the criteria for stress-test interruption are lacking. There was heterogeneity in the methodologies employed to perform the measurements, in the inclusion/exclusion criteria (often not reported), in the data normalization and the data expression (Z-scores/percentiles/mean values). Although most studies adjusted the measurements for age and/or height, the classification by specific age/height subgroups varied. Gender differences were generally considered, whereas other confounders (that is, ethnicity/geographic area/environment) were seldom evaluated. As a result, nomograms were heterogeneous, and when comparable, at times showed widely different confidence intervals. These differences are most likely because of both methodological limitations and differences among the populations studied. Some robust nomograms exist (particularly those from the USA); however, it has been demonstrated that if adopted in other countries/continents, they may generate an unpredictable bias in the evaluation of BP values in children. Actual pediatric BP nomograms present consistent limitations that affect the evaluation of BP in children. Comprehensive nomograms, which are based on a large population of healthy children (including neonates/infants) and use standardized methodology, are warranted for every country/region.

First report on simplified diagnostic criteria for pre-hypertension and hypertension in a national sample of adolescents from the Middle East and North Africa: the CASPIAN-III study

OBJECTIVE

This study aimed to simplify the diagnostic criteria of pre-hypertension (pre-HTN) and hypertension (HTN) in the pediatric age group, and to determine the accuracy of these simple indexes in a nationally-representative sample of Iranian children and adolescents.

METHOD

The diagnostic accuracy of the indexes of systolic blood pressure-to-height ratio (SBPHR) and diastolic BPHR (DBPHR) to define pre-HTN and HTN was determined by the area under the curve of the receiver operator characteristic curves.

RESULTS

The study population consisted of 5,738 Iranian students (2,875 females) with mean (SD) age of 14.7 (2.4) years. The prevalences of pre-HTN and HTN were 6.9% and 5.6%. The optimal thresholds for defining pre-HTN were 0.73 in males and 0.71 in females for SBPHR, and 0.47 in males and 0.45 in females for DBPHR, respectively. The corresponding figures for HTN were 0.73, 0.71, 0.48, and 0.46, respectively. In both genders, the accuracies of SBPHR and DBPHR in diagnosing pre-HTN and HTN were approximately 80%.

CONCLUSIONS

BPHR is a valid, simple, inexpensive, and accurate tool to diagnose pre-HTN and HTN in adolescents. The optimal thresholds of SBPHR and DBPHR were consistent with the corresponding figures in other populations of children and adolescents with different racial and ethnic backgrounds. Thus, it is suggested that the use of these indexes can be generalized in programs aiming to screen elevated blood pressure in the pediatric age group.