White-coat hypertension: growing evidence in favour of its adverse prognostic significance
In the last 10 years, several meta-analyses have looked at the risk of cardiovascular outcomes in white-coat hypertension (WCH), that is the condition in which office blood pressure (BP) is elevated, whereas ambulatory or home BP is normal . In two earlier meta-analyses, respectively, published in 2007 and 2008, cardiovascular risk was found not to differ significantly in WCH and normotension [2,3]. This was not the case in a meta-analysis published in 2016, in which individuals with WCH were found to have a significantly greater risk of cardiovascular events and mortality (+73 and 179%) compared with normotensive controls . It is now shown not to be the case also in a comprehensive meta-analysis of 12 cohorts (21 336 patients) published by Huang et al. in this issue of the Journal of Hypertension, in which WCH exhibited, over an average follow-up of about 8 years, a slight but significant increase of cardiovascular diseases (19%) and all-cause death (50%) compared with normotensive controls. This reinforces the conclusion that WCH is not clinically innocent  but that it rather identifies patients in whom the risk of clinically manifesting cardiovascular disease or death over the following few years is greater than that of the normotensive population. It also confirms the appropriateness of the recommendation of European Hypertension Guidelines that WCH needs a follow-up closer than that reserved to individuals in whom office and out-of-office BP are within the normal range . This is further supported by the evidence that in WCH there is a significant increase in the risk of developing a true hypertensive condition (i.e. an in and out-of-office BP elevation) or diabetes over a 10-year time interval, with thus a more frequent midterm progression to a high cardiovascular risk state [7,8].