Impact of masking effect on subclinical carotid atherosclerosis in normotensives and untreated masked hypertensive and hypertensive patients.

OBJECTIVES: The masking effect (ME) is present in masked hypertensive patients; however, both normotensive and hypertensive individuals may show a similar phenomenon. Previous studies have shown that ME has been associated with left ventricular hypertrophy and microalbuminuria in treated hypertensive patients. The aim of our study was to evaluate the association between the magnitude of systolic ME and the extent of common carotid artery intima-media thickness (CCA-IMT) development in normotensive individuals and untreated masked hypertensive and hypertensive patients.

PARTICIPANTS AND METHODS: A total of 1154 individuals underwent 24 h ambulatory blood pressure (BP) monitoring and carotid artery ultrasonographic measurements. The final study population included 360 patients with systolic ME (daytime systolic BP higher than office systolic BP). The participants were divided into three groups according to office and daytime BP values: normotensives, masked hypertensives, and hypertensives.

RESULTS: Masked hypertensives presented significantly higher systolic ME (-14.6 mmHg) than their normotensive (-8.2 mmHg) and hypertensive (-9.5 mmHg) counterparts. However, systolic ME was associated significantly with CCA-IMT only in the group of masked hypertensives (r=-0.399, P<0.001). The multivariate linear regression analyses showed significant and independent associations of CCA-IMT with the following factors: age (B=0.028, 95% confidence interval: 0.001-0.055; P=0.044) and systolic ME (B=-0.034, 95% confidence interval: -0.066 to -0.003; P=0.034). A 10 mmHg decrease in systolic ME correlated to an increase of 0.034 mm in the CCA-IMT.

CONCLUSION: Systolic ME was associated significantly with CCA-IMT values in masked hypertensives. Both normotensive and hypertensive participants have failed to show similar associations.