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White coat hypertension (WCH) is persistent elevated blood pressure (BP) in medical settings in patients who have normal BP elsewhere. The usual explanation for WCH is stress-induced, exaggerated sympathetic activity. But does pediatric WCH represent a prehypertensive chronic condition?
Researchers retrospectively evaluated 119 consecutive children and adolescents (age range, 6–18 years; 65% male) who were referred to a tertiary center because they had systolic BP recorded by primary care clinicians that exceeded the 95th percentile for age, sex, and height. The children underwent ambulatory BP monitoring, treadmill testing, and echocardiograph measurement of left ventricular mass index (LVMI).
WCH was documented in 62 patients and true hypertension in 57 patients. Office systolic BP did not differ between the two groups; mean diastolic BP in the office was significantly, but not universally, higher in patients with true hypertension. Among males, mean ambulatory systolic BP was 142 mm Hg in those with hypertension and 125 mm Hg in those with WCH. Among females, these values were 137 and 121 mm Hg, respectively. BP during treadmill testing exceeded norms in 63% of hypertensive patients and 38% of patients with WCH. Echocardiograph measurement of LVMI was above the 95th percentile in 33% of males and 36% of females with WCH and in 59% of males and 90% of females with hypertension.
Kavey RE et al. White coat hypertension in childhood: Evidence for end-organ effect. J Pediatr 2007 May; 150:491-7.
Comment
The finding that a substantial number of children and adolescents with office-based, increased systolic BP also have elevation of LVMI (a measure of end-organ effects of elevated systolic BP) and abnormal treadmill tests suggests that these patients might be at risk for hypertension as adults. This conclusion is supported by the observation in adults that elevated LVMI is a strong independent predictor of increased risk for cardiovascular morbidity. The study is limited by the retrospective design and the select group of patients referred to a tertiary center. Persistent elevation of systolic BP (>95th percentile) in a primary care office, even with normal recordings at home, might reflect a physiologically benign condition caused by undetected stress and anxiety, but it could also be a harbinger of sustained hypertension.