WHITE-COAT HYPERTENSION: SIZE OF THE WHITE-COAT EFFECT IS STRONGLY ASSOCIATED WITH CENTRAL ARTERIAL STIFFNESS

Abstract

Objective: To explore the relationship between the systolic/diastolic white-coat effect (sWCE and dWCE), defined by the difference between clinic BP and mean daytime ambulatory BP, and central arterial stiffness. Design and method: The Brighton and Verona Seniors Study (BRAVES) recruited 184 healthy older adults aged 65–85 from primary care. Participants were not eligible for recruitment if they had known: cardiovascular disease, chronic kidney disease, diabetes, malignancy, smoking, statin therapy, or hormone therapy. Each participant was evaluated for office BP, anthropometrics, and cardiovascular risk factors. 24-hour ambulatory BP was measured using Diasys Integra II (Novacor, France). Carotid-femoral pulse wave velocity (cfPWV) and carotid-radial pulse wave velocity (crPWV) was measured using Complior (Alam Medical, France). 101 participants, not on antihypertensive therapy and with complete ambulatory readings, were selected for analysis. Participants were grouped by BP phenotype: normotension (NT), white-coat hypertension (WCH), masked hypertension (MH), and sustained hypertension (SH). Results: The 101 participants (mean age ± standard deviation: 72 ± 5 years) consisted of 32 NT, 34 WCH, 9 MH, and 26 SH. A positive correlation was seen between both sWCE (r = 0.21; p = 0.03) and dWCE (r = 0.34; p < 0.001) with cfPWV. The WCH subgroup analysis (n = 34) revealed a stronger association between sWCE (r = 0.44; p = 0.01) and dWCE (r = 0.74; p < 0.001) with cfPWV. There was no association in the other BP phenotypes. There was no association of crPWV with either sWCE or dWCE. Multivariable linear regression was conducted on sWCE and dWCE as dependent variables and age, gender, BMI and cfPWV as independent variables (sWCE model: R2 = 0.19; p = 0.23; dWCE model: R2 = 0.61, p < 0.001). After adjustment, a significant association remained between cfPWV and sWCE (B = 2.72, 95% CI 0.32–5.13, p = 0.03) and cfPWV and dWCE (B = 2.70, 95% CI 1.60–3.79, p < 0.001). Conclusions: In healthy older adults with WCH, sWCE and dWCE are independently associated with central arterial stiffness. Central arterial stiffness accounts for a greater proportion of the overall variance of dWCE than sWCE. The WCE is not associated with peripheral arterial stiffness. In WCH, a large WCE may identify individuals at a higher risk of cardiovascular events.