The diagnosis of hypertension in children is difficult because of the multiple sex-, age-, and height-specific thresholds to define elevated blood pressure (BP). Blood pressure-to-height ratio (BPHR) has been proposed to facilitate the identification of elevated BP in children.
We assessed the performance of BPHR at a single screening visit to identify children with hypertension that is sustained elevated BP.
In a school-based study conducted in Switzerland, BP was measured at up to three visits in 5207 children. Children had hypertension if BP was elevated at the three visits. Sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) for the identification of hypertension were assessed for different thresholds of BPHR. The ability of BPHR at a single screening visit to discriminate children with and without hypertension was evaluated with receiver operating characteristic (ROC) curve analyses.
The prevalence of systolic/diastolic hypertension was 2.2%. Systolic BPHR had a better performance to identify hypertension compared with diastolic BPHR (area under the ROC curve: 0.95 vs. 0.84). The highest performance was obtained with a systolic BPHR threshold set at 0.80 mmHg/cm (sensitivity: 98%; specificity: 85%; PPV: 12%; and NPV: 100%) and a diastolic BPHR threshold set at 0.45 mmHg/cm (sensitivity: 79%; specificity: 70%; PPV: 5%; and NPV: 99%). The PPV was higher among tall or overweight children.
BPHR at a single screening visit had a high performance to identify hypertension in children, although the low prevalence of hypertension led to a low PPV.
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aInstitute of Social and Preventive Medicine (IUMSP), Lausanne University Hospital, Lausanne
bUniversity Children's Hospital, Inselspital and University of Bern, Bern
cService of Nephrology, Lausanne University Hospital, Lausanne, Switzerland
dDepartment of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, Canada
Correspondence to Arnaud Chiolero, MD, PhD, Institute of Social and Preventive Medicine (IUMSP), University Hospital Center (CHUV/UNIL), Biopôle 2, Route de la Corniche 10, 1010 Lausanne, Switzerland. Tel: +41 21 314 72 72; fax: +41 21 314 73 73; e-mail: firstname.lastname@example.org
Abbreviations: AUC, area under the curve; BPHR, blood pressure-to-height ratio; NPV, negative predictive value; PPV, positive predictive value; ROC, receiver operating characteristic
Received 25 October, 2013
Revised 18 January, 2014
Accepted 27 January, 2014
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