148 P revious studies have estimated the prevalence of con- frmed hypertension in children to range between 2% and 4%. 1–3 These estimates were based on the 2004 Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents (FR). 4 In 2017, the American Academy of Pediatrics (AAP) issued the new Clinical Practice Guideline for Screening and Management of High Blood Pressure in Children and Adolescents (AAP) updating the criteria for hypertension diagnosis in children. 5 The Houston Pediatric and Adolescent Hypertension Program at the University of Texas McGovern Medical School at Houston conducts blood pressure (BP) screenings in middle and high schools in the Houston metropolitan area. We have previously published estimates of the prevalence of abnormal BP based on FR guidelines. 3 The goal of this study is to deter- mine how the new AAP guidelines alter the prevalence of BP classifcations in this community-based screening population. Methods The Committee for Protection of Human Subjects at the University of Texas Health Science Center at Houston (as well as local school district institutional review boards where required) has approved the collection and analysis of this study data but has not approved the sharing of data from this study outside the university. We will con- tinue to work with this committee to develop a data sharing plan as the study continues to collect data. Between 2000 and 2017, the Houston Pediatric and Adolescent Hypertension Program at the University of Texas McGovern Medical School at Houston completed school-based BP screenings in 28 middle and high schools. Schools were selected by convenience sampling with the goal of identifying a population with similar racial/ethnic distribution as the Houston metropolitan area. All students enrolled at selected schools were eligible to partic- ipate, with physical education classes as the primary point of contact. On the day of study visit, the screening was performed in lieu of reg- ular physical education activities. Individual consents were obtained from each student’s primary caretaker per local school district policy. In schools that did not require individual consents, all students were screened unless either the student or legal guardian declined. Participating students completed an open-ended questionnaire that identifed age, sex, racial/ethnic background, and use of an- tihypertensive medications. Our study personnel was composed of paramedics, medical students, pediatric residents, fellows, clinic nurses, and attending pediatric nephrologists. All people responsible for obtaining measurements were trained in the proper use of the e- quipment. Study personnel measured arm circumference (cm), height (cm), and weight (kg). Body mass index percentiles representing Received June 20, 2018; frst decision July 9, 2018; revision accepted October 9, 2018. From the Division of Pediatric Nephrology & Hypertension, McGovern Medical School at UTHealth Houston, TX. The online-only Data Supplement is available with this article at https://www.ahajournals.org/doi/suppl/10.1161/HYPERTENSIONAHA.118.11673. Correspondence to Cynthia S. Bell, Division of Pediatric Nephrology & Hypertension, Center for Clinical Research & Evidence-Based Medicine, McGovern Medical School at UTHealth, 6431 Fannin St, MSB 3.121, Houston, TX. Email Cynthia.Bell@uth.tmc.edu See Editorial Commentary, pp 31–32 Abstract—In 2017, the American Academy of Pediatrics issued a new clinical practice guideline for defning hypertension in children as an update to the previous Fourth Report guidelines issued in 2004. Prevalence of confrmed pediatric hypertension in children has ranged from 2% to 4% based on previous guidelines yet it is unknown what the prevalence is under the new guideline. We estimated the prevalence of elevated blood pressure, stage 1, and stage 2 hypertension by the new American Academy of Pediatrics guideline in our school-based blood pressure screening program. New prevalence estimates were compared with Fourth Report prevalence estimates in the same population by sex, age, and height factors. In 22 224 students aged 10 to 17 years screened in school as part of the Houston Pediatric and Hypertension Program at the University of Texas McGovern Medical School, the prevalence of elevated blood pressure (previously called prehypertension) increased from 14.8% by Fourth Report to 16.3% by the new American Academy of Pediatrics guideline. This increase in elevated blood pressure resulted from differential classifcation changes in younger and older children. Prevalence of confrmed hypertension remains at 2% to 4% in this population, however shorter children <13 years old and taller, older children 13+ years old are systematically more likely to be diagnosed with hypertension by new guidelines. (Hypertension. 2019;73:148-152. DOI: 10.1161/HYPERTENSIONAHA.118.11673.) • Online Data Supplement Key Words: blood pressure ◼ epidemiology ◼ hypertension ◼ pediatrics ◼ prehypertension ◼ prevalence Prevalence of Hypertension in Children Applying the New American Academy of Pediatrics Clinical Practice Guideline Cynthia S. Bell, Joyce P. Samuel, Joshua A. Samuels © 2018 The Authors. Hypertension is published on behalf of the American Heart Association, Inc., by Wolters Kluwer Health, Inc. This is an open access article under the terms of the Creative Commons Attribution Non-Commercial-NoDerivs License, which permits use, distribution, and reproduction in any medium, provided that the original work is properly cited, the use is noncommercial, and no modifcations or adaptations are made. Hypertension is available at https://www.ahajournals.org/journal/hyp DOI: 10.1161/HYPERTENSIONAHA.118.11673 Childhood Hypertension