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.