Simplification of childhood hypertension definition using blood pressure to height ratio among US youths aged 8–17 years, NHANES 1999–2012

Highlights

• The fourth report on HBP criteria is quite difficult for use by professionals in the clinic or children and their parents.

• The study was aimed to simplify the hypertension diagnostic criteria using BP to height ratio.

• Data were obtained from a national representative sample of 14,624 US children and adolescents aged 8–17 years.

• The optimal thresholds of BP to height ratio are simple and accurate for screening pre-hypertension and hypertension.

Abstract

Background

The fourth report on the diagnosis, evaluation, and treatment of high blood pressure (BP) established high BP diagnostic criteria using age-, sex-, and height-specific BP percentiles. However, these BP criteria are quite difficult for use by professionals in the clinic or children and their parents. We aimed to simplify the hypertension diagnostic criteria using BP to height ratio (BP/height) in US children and adolescents aged 8–17 years.

Methods

Data were obtained from a national representative sample of 14,624 US children and adolescents aged 8–17 years enrolled in the continuous National Health and Nutrition Examination Survey 1999–2012. SBP to height ratio (SBPHR) was calculated as SBP (mm Hg)/height (cm) and DBP to height ratio (DBPHR) was calculated as DBP (mm Hg)/height (cm). The BP diagnostic criteria recommended by the fourth report were used as the “gold standard”. Receive operator characteristic curve analysis was used to choose the optimal thresholds of SBPHR and DBPHR.

Results

The optimal thresholds for identifying pre-hypertension and hypertension among children aged 8–12 years and adolescents aged 13–17 years were determined. The negative predictive value (NPV) for identifying hypertension was nearly 100% for both children and adolescents, although the positive predictive value (PPV) ranged from 19% to 35%. The NPV for identifying pre-hypertension ranged from 95% to 99% for children and adolescents, and the PPV ranged from 11% to 52%.

Conclusions

The optimal thresholds of SBPHR and DBPHR are simple and accurate for screening elevated BP, although PPV is relatively low because of the low prevalence of childhood hypertension.

Introduction

Childhood hypertension is a serious health problem in the United States. Recent data suggested that the prevalence of elevated BP (defined as SBP or DBP ≥ 90th percentile, SBP ≥ 120 mm Hg or DBP ≥ 80 mm Hg) has increased in US children and adolescents aged 8–17 years (from 15.8% to 19.2% in boys and from 8.2% to 12.6% in girls) between 1988–1994 and 1999–2008 [1]. In addition, many studies have reported that adult hypertension originates from early life [2]. This evidence suggests the urgency for the prevention and control of childhood hypertension in the United States.

The US fourth report (2004) on the diagnosis, evaluation, and treatment of high BP in children and adolescents established high BP diagnostic criteria using SBP/DBP ≥ 90th percentile and < 95th percentile (or SBP/DBP ≥ 120/80 mm Hg) to define pre-hypertension and using SBP/DBP ≥ 95th percentile to define hypertension in US children and adolescents [3]. However, these BP criteria may be too complex for clinical use by medical professionals or by children and their parents because of the age-, sex- and height-specific criteria. It is also reported that hypertension in children may be under-diagnosed in clinical practice partially because of the complexity of these diagnostic criteria [4]. Therefore, it is time to establish a simple and acceptable BP standard to early identify the children with pre-hypertension and hypertension.

In this study, we aimed to simplify the hypertension diagnostic criteria using blood pressure to height ratio (BP/height) in 14,624 US children and adolescents aged 8–17 years enrolled in the continuous National Health and Nutrition Examination Survey (NHANES) between 1999 and 2012.