In contrast, masked hypertension is characterized by office readings sug- gesting normal BP but out-of-office (ABPM/HBPM) read- ings that are consistently above normal.S4.4-15 In sustained hypertension, BP readings are elevated in both office and out- of-office settings. In patients treated for hypertension, both white coat effect (higher office BPs than out-of-office BPs) and masked uncontrolled hypertension (controlled office BPs but uncontrolled BPs in out-of-office settings) categories have been reported.S4.4-5,S4.4-15,S4.4-16 The white coat effect (usu- ally considered clinically significant when office SBP/DBPs are >20/10 mm Hg higher than home or ABPM SBP/DBPs) has been implicated in pseudo-resistant hypertension (see Section 11.1) and results in an underestimation of office BP The prevalence of masked hyperten- sion varies from 10% to 26% (mean 13%) in population- based surveys and from 14% to 30% in normotensive clinic The risk of CVD and all-cause mortality in persons with masked hypertension is similar to that noted in those with sus- tained hypertension and about twice as high as the correspond- ing risk in their normotensive counterparts.S4.4-3,S4.4-4,S4.4-6,S4.4-8,S4.4-11 The prevalence of masked hypertension increases with higher office BP readings.S4.4-20,S4.4-22,S4.4-23 The prevalence of white coat hypertension is higher with female versus male sex, nonsmoking ver- sus current smoking status, and routine office measurement of BP by clinician observers versus unattended BP measure- ments. Many, but not all, studiesS4.4-4,S4.4-6,S4.4-8,S4.4-25,S4.4-26 have identified a minimal increase in risk of CVD complications or all-cause mortality in patients who have white coat hyperten- sion. 