New US Guidelines for Hypertension in Children and Adolescents

Linda Brookes, MSc

Disclosures

May 28, 2004

Editorial Collaboration

Medscape &

Presenter: Bonita Falkner, MD, Thomas Jefferson University (Philadelphia, Pennsylvania), Chair, National High Blood Pressure Education Program (NHBPEP) Working Group on High Blood Pressure in Children and Adolescents

New national guidelines for the diagnosis and treatment of hypertension in children are to be issued shortly in the United States by the National Heart, Lung, and Blood Institute (NHLBI) and the National High Blood Pressure Education Program (NHBPEP). The 4th Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents, which updates the previous 1996 report,[1] will be published in the July issue of Pediatrics, the journal published by the American Academy Of Pediatrics (http://pediatrics.aappublications.org/), and on the NHBLI Web site at http://www.nhlbi.nih.gov/guidelines/hypertension/child_tbl.htm.[2] The report is based on the latest data from the National Health and Nutrition Examination Survey (NHANES) conducted in 1999 and 2000[3,4,5] and conforms to the latest national hypertension guidelines for adults -- the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) -- issued last year.[6]

The new pediatric guidelines include a revised classification of blood pressure, a guide to the evaluation of hypertension in children, rationale and recommendations for identification and treatment of target organ damage, and updated recommendations for lifestyle changes and antihypertensive drug therapy.

Definitions and Classifications

Hypertension in children is defined by percentiles, analogously to the "IQ" ranking of intelligence. This means that blood pressure readings are ranked according to where they fall against the percentage of the reference population of all children, while taking into account variations in body weight, height, age, and other developmental parameters. The updated blood pressure tables, based on the NHANES 1999-2000 data, now include the 50th, 90th, 95th, and 99th percentiles. The 50th percentile has been added to provide the clinician with the midpoint of normal blood pressure range. The 99th percentile has been added to allow more precise staging of hypertension, which begins at the 95th percentile (ie, a child whose blood pressure is higher than that of 95% of other children of similar age, weight, and height is "hypertensive").

The new blood pressure classification introduces the "prehypertension" category first used in JNC 7 (Table). In children, prehypertension is defined as average systolic-diastolic blood pressure (SBP/DBP) ≥ 90th and < 95th percentiles (previously defined as "high normal"). It was noticed in the blood pressure tables, however, that at age 12 years in boys and 13 years in girls, the 95th percentile goes above SBP 120 mm Hg, so adolescents with blood pressure ≥ 120/80 mm Hg should be considered hypertensive. The report recommends that if the blood pressure obtained in the office is > 90th percentile, a repeat measurement should be taken during the same office visit.

The definition of hypertension remains unchanged, at SBP and/or DBP ≥ 95th percentile for age, gender, and height measured on ≥ 3 separate occasions. If the blood pressure measurement obtained in the office is > 95th percentile -- ie, the child is hypertensive -- then the degree of hypertension should be staged. To do this, 5 mm Hg is added to the ranges for stage 1 (95th-99th percentile) and stage 2 (> 99th percentile) (see Table).

Table. Classification of Blood Pressure in Children and Adolescents
Blood Pressure Category Definition
Normal < 90th percentile
Prehypertension 90th-95th percentile
or 120/80 mm Hg
Hypertension
Stage 1 95th-99th percentile + 5 mm Hg
Stage 2 > 99th percentile + 5 mm Hg

The term "white coat" hypertension has been included for the first time, and is said to exist when an individual whose blood pressure is > 95th percentile in the physician's office or clinic but who is normotensive outside this setting. Ambulatory blood pressure monitoring (ABPM) is required to make this diagnosis.

Therapy

The new report also serves as a guide to steps in therapy. It recommends that even children who are normotensive be "encouraged" with regard to physical activity, a healthy diet, and sleep. Weight management and diet management counseling for the overweight and introduction of physical activity should be "instituted or strongly encouraged" in children who are prehypertensive and as initial therapy in those who are hypertensive, according to the report.

Pharmacologic therapy may be appropriate for prehypertension if there are compelling indications such as renal disease, diabetes, or signs of left ventricular hypertrophy, the report says. For stage 1 hypertension, pharmacologic therapy should be initiated on the basis of indications, and in stage 2 it is recommended that unless there is a dramatic response to lifestyle changes, pharmacologic therapy should be given. Pharmacologic therapy should always begin with a single drug, such as an angiotensin-converting enzyme inhibitor, angiotensin receptor blocker, beta-blocker, calcium channel blocker, or diuretic. More data have become available on pediatric use of antihypertensive medications since the enactment of the Food and Drug Administration Modernization Act, which called for clinical trials involving children, the report notes.

Guidelines for the clinical evaluation of hypertension are included in the report. It includes stage 1-2 basic evaluation, but also, for the first time, recommendations for identifying comorbidities, ie, associated risk factors for cardiovascular disease, particularly obesity, lipid disorders, glucose metabolism abnormalities including familial history of diabetes, and sleep disorders. (Sleep apnea has been linked in studies to childhood hypertension.)

The report also recommends that children should be evaluated for target organ damage. Evidence has emerged that children with hypertension may have left ventricular hypertrophy and that they should have an echocardiogram as part of their evaluation. Further evaluation, such as ABPM, may be required as indicated, particularly to diagnose white coat hypertension.

The working group repeats the previous recommendation that blood pressure should be measured in children aged 3 years and upward, starting earlier in preterm infants.

Benefits of Early Detection of Hypertension

In the May 20th issue of The New England Journal of Medicine, deputy editor Julie R Ingelfinger, MD, Harvard Medical School and Massachusetts General Hospital for Children (Boston, Massachusetts), who was a member of the guidelines Working Group, stresses the importance and potential benefits of early recognition of hypertension for introducing early interventions and reducing cardiovascular mortality among adults.[7] She defends the use of the term prehypertension in children and adolescents as serving as "a signal to institute healthful lifestyle changes that might avert future cardiovascular disease." While admitting that "many physicians are still not familiar with the best way to evaluate and treat children with high blood pressure," she is hopeful that the working group's new report will "constitute a call to action."

Prevalence of Hypertension Increasing in Children

The new guidelines stress that hypertension is a significant health issue in children. According to Dr. Falkner, 1% to 3% of children and adolescents may have hypertension. A recent analysis of data from NHANES III (1988-1994) and NHANES (1999-2000) by researchers at Tulane University (New Orleans, Louisiana) and the NHLBI (Bethesda, Maryland) showed that blood pressure in US children and adolescents rose between the time of the 2 surveys.[8] The rise in DBP was particularly significant, at an average of 2.2 mm Hg, while SBP rose by an average of 1.4 mm Hg. A strong association between body mass index and SBP identified among children suggests that this increase in blood pressure is at least in part attributable to an increased prevalence of overweight.

References
  1. National High Blood Pressure Education Program. Update on the 1987 Task Force Report on High Blood Pressure in Children and Adolescents: A working group report from the National High Blood Pressure Education Program. National High Blood Pressure Education Program Working Group on Hypertension Control in Children and Adolescents. Pediatrics. 1996;98:649-658.

  2. Fourth Report on the Diagnosis, Evaluation, and Treatment of High Blood Pressure in Children and Adolescents. Pediatrics. In press. To be made available at
    http://www.nhlbi.nih.gov/guidelines/hypertension/child_tbl.htm.

  3. NHANES 1999-2000 public data release file documentation. Available at
    http://www.cdc.gov/nchs/data/nhanes/gendoc.pdf. Accessed May 27, 2004.

  4. Blood pressure section of the physician examination, NHANES 1999-2000. Available at
    http://www.cdc.gov/nchs/about/major/nhanes/NHANES99_00.htm. Accessed May 27, 2004.

  5. NHANES 1999-2000 addendum to the NHANES III analytical guidelines. Available at
    http://www.cdc.gov/nchs/data//nhanes/guidelines1.pdf. Accessed May 27, 2004.

  6. Chobanian AV, Bakris GL, Black HR, et al. Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. Hypertension. 2003;42:1206-1252.

  7. Ingelfinger JR. Pediatric antecedents of adult cardiovascular disease – Awareness and intervention. N Engl J Med. 2004;350:2123-2126.

  8. Munter P, He J, Cutler JA, et al. Trends in blood pressure among children and adolescents. JAMA. 2004;291:2107-2113.

 

Comments

3090D553-9492-4563-8681-AD288FA52ACE

processing....