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

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.