Sequential follow-up clinic and ambulatory blood pressure evaluation in a low risk population of white-coat hypertensive patients and in normotensives

Abstract

Background: In subjects with white-coat hypertension (WCH) it is unclear how ambulatory blood pressure (ABPM) progresses over time and whether they exhibit an increased cardiovascular risk.

Methods: We prospectively evaluated the transition of clinic and ABPM values in 39 clinic and ABPM normotensive subjects (NT) (clinic BP<140/90 mmHg and awake BP<130/85 mmHg, ages 43.4+/-2.6 y) and in 79 untreated subjects (47.2+/-2.4 y) with WCH (clinic BP>140/90, awake ABP<130/85 mmHg) with no other major cardiovascular risk factors. Ambulatory blood pressure was evaluated at baseline and on at least two further occasions during follow-up.

Results: At baseline all subjects were untreated and groups did not differ on values of metabolic parameters, BMI, left ventricular mass index, and ABPM values. Subjects were revaluated for ABPM half way through and at the end of follow-up, 35+/-3 and 86+/-4 months in NT and 49+/-4 and 90+/-4 months in WCH. Thirty-six WCH were on antihypertensive treatment (AH) after baseline until the end of follow-up (WCH-tr), whereas 43 WCH (WCH-untr) were free from AH throughout the study. In a similar way all groups showed a significant (p<0.01) progressive increase in 24-h ABPM systolic blood pressure (SBP)/diastolic blood pressure (DBP) from baseline throughout the follow-up in NT (+4.9/2.1+/-0.8/0.9 mmHg), average annual increase of 0.72/0.37 mmHg/y, in WCH-tr (+ 5.0/1.2+/-1.1/1.5 mmHg), average annual increase of 0.66/0.31 mmHg/y and in WCH-untr (+5.4/3.2+/-0.9/1.1 mmHg), average annual increase of 0.74/0.39 mmHg/y. During the follow-up office SBP/DBP (mmHg) significantly rose in NT (+5.7/3.9) but was reduced in WCH-tr (-7.8/5.2) and in WCH-untr (-4.7/1.1). Development of ambulatory hypertension (daytime BP >130 and/or >85 mmHg) occurred in 15.4% (6/39) of NT, in 22.7% (8/36) of WCH-tr and in 26.1% (11/43) of WCH-untr (NS). First cardiovascular events recorded were three in subjects with WCH and none in NT.

Conclusions: After 7.4 years of follow-up, both the progressive increase in ABPM and the rate of transition to ambulatory hypertension in subjects with WCH (either treated or untreated), who were selected under strict criteria were similar to that of normotensive subjects. Also there was no evidence that WCH exhibited a clear higher risk of development cardiovascular events.