In Practice
Improving Diagnostic Accuracy for Pediatric Hypertension A recent pilot study highlights additional diagnostic criteria for clinicians to consider. Despite the availability of normative MAP values, current pediatric guidelines recommend using these calculated systolic and diastolic BP values rather than the measured MAP for hypertension diagnosis. A recent pilot study challenged those guidelines. Published in Pediatric Nephrology and led by Dr. Kallash, the retrospective study of 263 patients found that considering the measured MAP values significantly improved diagnostic accuracy.
P
ediatric hypertension, or high blood pressure (BP), has become increasingly common and now affects more than 3% of children and adolescents. Untreated, hypertension is one of the strongest risk factors for cardiovascular disease and mortality in adults, and substantial evidence links childhood hypertension to long-term renal, cardiovascular and neurodevelopment risks. To avoid underdiagnosis, evaluation of BP percentiles should be a routine part of pediatric practice, but hypertension is more challenging to diagnose in children because of age-, sex- and height-related variability in BP norms. Over the last decade, ambulatory BP monitoring (ABPM) has become the standard for diagnosing hypertension in children. “Without using ABPM, the chance of making an error in your diagnosis is close to 40%, so the guidelines strongly recommend using ABPM,” says Mahmoud Kallash, MD, a physician in the Division of Pediatric Nephrology and Hypertension at Nationwide Children’s Hospital. ABPM uses oscillometric machines to measure mean arterial pressure (MAP) by automatically collecting a series of readings over 24 hours while patients are at home. From there, systolic and diastolic BP values are extrapolated based on manufacturer-specific formulas.
4
PediatricsNationwide.org | Fall/Winter 2020
Additionally, this study was the first to investigate using adult criteria for diagnosing hypertension in male children who are greater than 165 cm tall. For this group, the 95th percentile (hypertensive threshold) for average systolic and diastolic BP calculated using ABPM is higher than the hypertensive threshold used to define hypertension in adults. As a result, tall male children could have an ABPM study that would not result in a diagnosis of hypertension using pediatric criteria but would be interpreted as hypertension using adult criteria. When adult thresholds for diagnosis of ambulatory hypertension were applied, 10 subjects were hypertensive who were not categorized this way under pediatric criteria. As a result, using the higher pediatric thresholds for this subgroup may allow patients who are at risk for cardiovascular complications to go undiagnosed. Both under- and over-diagnosis of pediatric hypertension can have negative effects on children. “Patients with chronic kidney disease or heart disease may already take many medications and adding an unnecessary medication can have a major effect on their physical and mental health,” says Dr. Kallash. “Also, if left untreated, hypertension can result in a faster progression of patients’ renal or cardiac disease.” Thomas J, Stonebrook E, Klamer B, Patel HP, Kallash M. Challenges of diagnosing pediatric hypertension using ambulatory blood pressure monitoring. Pediatric Nephrology. 2020 Aug 6 [Epub ahead of print].
— Natalie Wilson
