Tuesday, August 29, 2017

Taking stock of a new guideline for hypertension in children

- Kenny Lin, MD, MPH

Last week, the American Academy of Pediatrics (AAP) published a new practice guideline on screening, evaluation and management of high blood pressure in children and adolescents, updating a 2004 guideline from the National Heart, Lung, and Blood Institute. The new guideline includes 30 evidence-informed "key action statements" and 27 other recommendations based on consensus opinion. The AAP recommends that blood pressure be measured annually in every child starting at 3 years of age, and at every health care encounter in children with obesity, renal disease, diabetes, aortic arch obstruction or coarctation, or who are taking medications known to increase blood pressure. Notably, the guideline's blood pressure tables lower previous thresholds for abnormal blood pressure in children by several mmHg because they are based on normal weight children only.

The American Academy of Family Physicians (AAFP) currently supports the U.S. Preventive Services Task Force's (USPSTF) 2013 statement that "current evidence is insufficient to assess the balance of benefits and harms of screening for primary hypertension in asymptomatic children and adolescents to prevent subsequent cardiovascular disease in childhood or adulthood." According to the USPSTF, the accuracy and reliability of blood pressure screening protocols in children has not been well studied; a sizable percentage of persons with high blood pressure in childhood will have normal blood pressure as adults; and there is inadequate evidence that lifestyle modification or pharmacotherapy results in sustained blood pressure decreases in children or prevents cardiovascular events. Also, abnormal blood pressure thresholds in the AAP guideline are based on a normal population distribution (with 3 different readings >95th percentile defined as hypertensive) rather than on patient-oriented evidence of improved outcomes, as in the JNC-8 guidelines for hypertension management in adults.

How can family physicians know if a new guideline is trustworthy and applicable to their patients? In a 2009 AFP article, Dr. David Slawson and I proposed several attributes of good practice guidelines:
  • Comprehensive, systematic evidence search with end date noted
  • Evidence linked directly to recommendations via strength of recommendation grading system
  • Recommendations based on patient-oriented rather than disease-oriented outcomes
  • Transparent guideline development process
  • Potential conflicts of interest identified and addressed
  • Prospectively validated (i.e., guideline use has been shown to improve patient-oriented outcomes)
  • Recommendations offer flexibility in various clinical situations
Subsequently, the Institute of Medicine (IOM; now the National Academy of Medicine) published a report, "Clinical Practice Guidelines We Can Trust," that recommended many similar criteria. The IOM report informed the American Academy of Family Physicians' current processes for developing and endorsing clinical practice guidelines from other organizations. The AAP guideline will undergo a structured quality assessment by AAFP staff and members of the Commission on the Health of the Public and Science, who will recommend to the Board of Directors if the guideline should be fully endorsed, receive an Affirmation of Value, or not endorsed. So stay tuned for more news and analysis of this guideline in future issues of AFP.