Lack of association between body-mass index and white-coat hypertension among referred patients.

OBJECTIVE

The association between body-mass index and ambulatory blood pressure variables is not straightforward. Specifically, there are contradicting data regarding the correlation between obesity and white-coat hypertension. The aim of this report was to study the relationship between body-mass index and the white-coat effect, defined by ambulatory monitoring.

METHODS

A retrospective analysis of a prospectively collected ambulatory blood pressure monitoring laboratory database was performed. We analyzed 3928 unselected ambulatory monitoring sessions of nontreated (n=1654) and treated (n=2274) patients, for statistical associations between body-mass index and blood pressure variables. Body-mass index was categorized according to National Institutes of Health classification or quartiles.

RESULTS

Office and ambulatory blood pressure variables correlated with body-mass index in untreated patients. Unadjusted, the systolic white-coat effect did not differ by body-mass index category, whereas the diastolic effect was higher in obese patients. Adjustment for age, sex and office blood pressure revealed inverse associations of body-mass index category with the systolic white-coat effect, in both untreated and treated patients. When determined categorically, neither overweight/obese untreated or treated patients had increased prevalence of white-coat hypertension. Multivariate linear regression models confirmed the negative correlation between body-mass index and the systolic white-coat effect in untreated (beta=-0.24, P<0.0001) and treated (beta=-0.14, P<0.05) patients.

CONCLUSION

In patients referred for ambulatory blood pressure monitoring there was no association between body-mass index and white-coat hypertension.