Journal of Human Hypertension (2011) 25, 623–624
& 2011 Macmillan Publishers Limited All rights reserved 0950-9240/11
www.nature.com/jhh
LETTER TO THE EDITOR
Evaluation of blood pressure/height ratio
as an index to simplify diagnostic criteria
of hypertension in Caucasian adolescents
Journal of Human Hypertension (2011) 25, 623–624;
doi:10.1038/jhh.2011.32; published online 12 May 2011
as follows: SBPHR ¼ SBP (mm Hg)/height (cm) and
DBPHR ¼ DBP (mm Hg)/height (cm). All measurements were performed during ordinary school time.
Statistical analyses were performed using the SAS
V9 software.4 Mean and standard deviation of
descriptive data were calculated. Pearson’s correlation coefficient was used to test the association
between variables, in order to confirm the Chinese
data. Prevalence of stage 1 and stage 2 hypertension
was calculated according to the 2004 Working Group
definition (gold standard) and BPHR cut-off points
provided by Lu and co-workers;1 specificity and
sensibility of the index applied in our population
against the gold standard were calculated.
Table 1 shows the clinical characteristics of the
studied population. Boys had significantly higher
height, weight and systolic blood pressure (SBP) than
girls (Po0.01) who had higher diastolic blood
pressure (DBP) values (Po0.04). Overall, 24% of
males and 19% of females were obese. The prevalence of hypertension according to the 2004 Working Group definition was 15.32% (0.96% stage 2) in
boys and 14.95% (2.05% stage 2) in girls. SBPHR and
DBPHR were not correlated with age and height in
both sexes, but positively correlated with BP values.
In a recent issue of this journal, Lu and co-workers1
found that blood pressure/height ratio (BPHR) was a
simple and accurate index for screening hypertension in Han adolescents. However, they suggested
that this index had to be validated in other ethnic
groups. We tested the applicability of this index
on a population of 1413 Caucasian adolescents (705
females and 698 males, age range 12–15 years),
evaluated in a cross-sectional population-based
study conducted among students of public junior
high schools of Turin, Italy.2 Hypertension was
defined according to the 2004 National High Blood
Pressure Education Program Working Group definition, and blood pressure measurements were
performed according to the 2004 working group
standards.3 The considered anthropometric parameters were height and weight: height, measured
barefoot with a right-angle ruler placed on the top of
the head and a tape measure fixed to the wall, and
weight of barefoot, undressed child measured with
an electronic scale. Obesity was defined by body
mass index X95th percentiles. BPHR was calculated
Table 1 Clinical characteristics of general population and sensitivity/specificity in Caucasian adolescents aged 12–15 years using
Lu et al.1 SBPHR and DBPHR thresholds
Variable
Height (cm)
Weight (kg)
BMI (kg m–2)
SBP (mm Hg)
DBP (mm Hg)
SBPHR (mm Hg cm–1)
DBPHR (mm Hg cm–1)
Boys (n ¼ 731)
Girls (n ¼ 682)
t-test
P-value
159.5±9.4
51.8±11.3
20.2±3.3
113.9±11.3
54.54±27.2
0.71±0.06
0.34±0.17
156±6.7
49.5±9.1
20.3±3.2
110.8±11.3
57.3±24.6
0.71±0.07
0.37±0.16
–7.92
–4.21
0.33
–4.82
2.00
–1.10
2.81
o.0001
o.0001
0.742
o.0001
0.0461
0.273
0.005
SBP 495th percentile
Thresholds
Sensitivity
Specificity
Boys
0.75
0.83
0.97
Girls
0.78
0.94
0.92
SBP 499th percentile+5 mm Hg
Thresholds
Sensitivity
Specificity
0.81
0.94
1.00
0.84
0.98
1.00
DBP 495th percentile
Boys
0.48
0.91
1.00
Girls
0.51
0.99
1.00
DBP 499th percentile+5 mm Hg
0.57
1.00
—
0.63
1.00
0.33
Abbreviations: BMI, body mass index; DBP, diastolic blood pressure; DBPHR, diastolic blood pressure-to-height ratio; SBP, systolic blood
pressure; SBPHR, systolic blood pressure-to-height ratio; Sens, a/a+c; Spec, d/b+d.
Letter to the Editor
624
Calculations of sensitivity and specificity with
the cut-off points provided by Lu and co-workers1
are shown in Table 1. For stage 1, hypertension
sensitivity and specificity X90% was found in both
sexes. For stage 2, sensitivity was about 1 in both
sexes for SBP and DBP, specificity was 1 for SBP and
invaluable for DBP due to the low number of cases.
Our data confirm the accuracy of BPHR in the
diagnosis of arterial hypertension in a representative
sample of Caucasian adolescents. The population
we studied was comparable for age and anthropometric parameters with the Chinese sample by
Lu and co-workers1. As in Chinese population, we
found stage 1 hypertension to be more common,
whereas, the prevalence of hypertension was higher
in our population (15 vs 6%). These data are
probably related to the higher prevalence of obesity
in our adolescents (20 vs 7.6%). We conclude that
BPHR may be a simple and accurate index for
hypertension screening also in Caucasian adolescents, and thus may have a wide applicability.
What is known about this topic
K Diagnosis of hypertension in adolescence is difficult
because of the need of several percentile grids. Recently,
blood pressure-to-height ratio has been validated as an
accurate index for identifying hypertension in Han
adolescents.
What this study adds
K Blood pressure-to-height ratio is an accurate index for
hypertension screening also in Caucasian adolescents, and
thus may have a wide applicability.
Journal of Human Hypertension
Conflict of interest
The authors declare no conflict of interest.
F Rabbia1, I Rabbone2, S Totaro1, E Testa1,
M Covella1, E Berra1, MC Bertello2, E Gioia2,
F Cerutti2 and F Veglio1
1
Department of Medicine and Experimental
Oncology, Division of Internal Medicine,
Hypertension Unit, University Hospital ‘S Giovanni
Battista’, Torino, Italy and
2
Department of Paediatrics, University of Turin,
Torino, Italy.
E-mail: [email protected]
Published online 12 May 2011
References
1 Lu Q, Ma CM, Yin FZ, Liu BW, Lou DH, Liu XL. How to
simplify the diagnostic criteria of hypertension in
adolescents. J Hum Hypertens 2011; 25(3): 159–163.
2 Rabbia F, Grosso T, Cat Genova G, Conterno A, De Vito
B, Mulatero P et al. Assessing resting heart rate in
adolescents: determinants and correlates. J Hum Hypertens 2002; 16(5): 327–332.
3 National High Blood Pressure Education Program Working Group on High Blood Pressure in Children Adolescents. The fourth report on the diagnosis, evaluation,
and treatment of high blood pressure in children and
adolescents. Pediatrics 2004; 114(2 Suppl 4th Report):
555–576.
4 SAS Institute Inc. SAS/STAT user’ s Guide. SAS
Institute Inc.: Cary, NC, 1988.