Untreated masked hypertension and carotid atherosclerosis: A meta-analysis

Aim. Masked hypertension (MH) is recognized as a clinical entity with an unfavorable cardiovascular prognosis; a limited number of reports, however, investigated the impact of this condition on subclinical vascular damage. We performed a meta-analysis aimed at evaluating the association of MH with subclinical carotid atherosclerosis in initially untreated subjects. Design. Studies were identified by the following search terms: "masked hypertension", "isolated clinic normotension", "white coat normotension", "carotid artery", "carotid atherosclerosis", "carotid intima-media thickness", "carotid damage" and "carotid thickening". Full articles published in English language reporting data from studies performed in untreated adult individuals were considered. Results. Overall, 2752 untreated subjects (1039 normotensive, 497 MH and 766 hypertensive individuals) of both genders were included in five studies (sample size range 18-222 for MH participants). Common carotid intima-media thickness (IMT) showed a progressive increase from normotensive (681 ± 24 μm) to MH (763 ± 57 μm) (standardized mean difference, SMD: 0.51 ± 0.19, 95% CI 0.13-0.89, p < 0.01) and to sustained hypertensive subjects (787 ± 58 μm) (SMD: 0.33 ± 0.07, 95% CI 0.20-0.46, p < 0.01). The statistical difference between MH and NT became borderline after correction for publication bias. A sensitivity analysis showed that the final result was not substantially affected by a single study effect. Conclusions. Our findings support the view that MH subjects tend to have a higher risk of developing early carotid atherosclerosis than their true normotensive counterparts. From a practical perspective, the ultrasound search of preclinical carotid disease may improve cardiovascular risk stratification and decision making strategies in these subjects.