Objective: Several studies have demonstrated that subjects with white-coat hypertension (WCH) have an increased risk of adverse cardiovascular outcome and target organ damage (TOD) progression compared to normotensives. The potentially detrimental effect of non-dipping or nocturnal hypertension on TOD has not been fully elucidated in subjects with WCH. The aim of our study was to investigate the impact of both dipping status and nocturnal hypertension on the left ventricle mass index (LVMI) of WCH individuals. Design and method: A total of 387 untreated WCH subjects underwent echocardiographic measurements. LVM was estimated using Devereux's formula according to the Penn Convention Protocol. LVMI was defined as LVM divided by the body surface area. The study population was divided into dippers (blood pressure (BP) nocturnal fall >10%) and non-dippers (BP nocturnal fall <10%) as well as into nocturnal hypertensives (nighttime systolic BP> = 120mmHg or nighttime diastolic BP> = 70mmHg) and nocturnal normotensives (nighttime systolic BP<120mmHg and nighttime diastolic BP<70mmHg). Statistical analysis was performed by means of independent-samples t-test, chi-square test and linear regression. Results: The percentages of non-dippers and nocturnal hypertensives in WCH subjects were 49% and 28%, respectively. The variables associated with LVMI in the univariate analyses were: age, male gender, body mass index, 24-hour diastolic BP and non-dippers. The multivariate regression analyses demonstrated significant associations of LVMI with the following factors: age (B = 5.760, 95% CI: 3.282 to 8.239; p<0.001), male gender (B = 10.941, 95% CI: 5.756 to 16.125; p<0.001), body mass index (B = 0.685, 95% CI: 0.138 to 1.232; p = 0.014), 24-hour diastolic BP (B = -6.634, 95% CI: -11.212 to -1.456; p<0.011) and non-dippers (B = 8.415, 95% CI: 3.449 to 13.380; p = 0.001). Non-dipping pattern was correlated to an increase of 8.415 g/m2 in the LVMI in WCH subjects. Conclusions: Non-dipping status is positively and independently associated with LVMI in untreated WCH patients. In contrast, statistically significant association between nocturnal hypertension and LVMI was not observed.
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