Is white-coat hypertension a risk factor for carotid atherosclerosis? A review and meta-analysis

The association of white-coat hypertension (WCH) with target organ damage is still debated; in particular, the relationship of this blood pressure phenotype with subclinical vascular damage remains controversial. Thus, we carried out a systematic review and meta-analysis to provide updated information on carotid structural changes in WCH. Studies were identified using the following search terms: 'white coat hypertension', 'isolated clinic hypertension', 'carotid artery', 'carotid atherosclerosis', 'carotid intima-media thickness', 'carotid damage', 'carotid thickening'. Full articles published in the English language in the last two decades reporting studies on adults were considered. A total of 3478 untreated patients, 940 normotensive (48% men), 666 WCH (48% men), and 1872 hypertensive individuals (57% men) included in 10 studies, were analyzed. Common carotid intima-media thickness (IMT) showed a progressive increase from normotensive (718± 36 μm) to WCH (763± 47 μm, standardized mean difference 0.54 ±0.13, P<0.01) and to hypertensive patients IMT (817±47 μm, standardized mean difference 0.45 ± 0.14, P<0.01). After assessing data for publication bias, only the difference between normotensive and WCH patients remained significant. Our meta-analysis documents that common carotid IMT, a prognostically validated marker of vascular damage, is greater in WCH patients than in true normotensive individuals and is not different from sustained hypertensives. This finding supports the concept that WCH is not an entirely benign condition.