White-Coat Hypertension: Do We Really Understand It Now?

Abstract

Arterial hypertension constitutes the most relevant cardiovascular risk factor due to its very high prevalence in the general population. An adequate estimation of blood pressure (BP) values is fundamental for an adequate evaluation of the accompanying risk as well as to establish the required amount of therapy to attain an adequate control. In this sense, office BP measurement does not always represent the real level of this parameter due to the frequent over- or underestimation of BP values in the office. Overestimation of BP levels in the office is known as the white-coat effect. When office BP is systematically elevated and out-of-office measurement, through ambulatory or home BP monitoring (ABPM, HBPM), is normal, the situation is known as white-coat hypertension (WCH). In untreated subjects, WCH is accompanied by an increase in risk when compared to sustained normotensives. In the case of treated hypertensives, it indicates that no further increases in the amount of medication are needed. Long-term follow-up is required in every case but ensuring an adequate estimation of BP through either ABPM or HBPM, albeit automated BP measurement in the office could also contribute to facilitate an adequate evaluation of BP discarding WCH. In untreated subjects, WCH frequently transforms with time into sustained hypertension.

Underestimation of BP values in the office, known as masked hypertension, is also frequent both in untreated and treated hypertensives. Actual guidelines recognize the need to treat pharmacologically untreated masked hypertensives. In treated hypertensives, the finding of elevated BP outside the office represents a situation of increased risk and probably also requires a more aggressive intervention.