Are the cardiovascular outcomes of participants with white-coat hypertension poor compared to those of participants with normotension? A systemic review and meta-analysis

The prognostic value of white-coat hypertension (WCH) remains controversial. We undertook a quantitative literature review to assess the risk of cardiovascular outcomes in untreated participants with WCH compared to that in participants with normotension. We searched databases (PubMed, Cochrane Library and the Ichu-Shi Web Japanese database) for peer-reviewed articles published until December 23, 2017 reporting studies evaluating the risk of cardiovascular outcomes in participants with WCH compared to that in participants with normotension. WCH was defined by having hypertension according to the conventional office blood pressure (BP) and being in the normotensive range (definitions of hypertension and normotension differed according to studies) for out-of-office BP measured at home or in an ambulatory setting. In total, 11 studies were included in the meta-analysis, which assessed the composite outcomes of morbidity and mortality on cardiovascular, stroke, and cardiac diseases, all-cause mortality, and deterioration to sustained hypertension in 8 (n = 11971), 2 (n = 6252), 2 (n = 6252), 5 (n = 10611), and 3 (n = 1722) studies, respectively. The risks for cardiovascular outcome and deterioration to sustained hypertension were significantly higher in WCH participants, with relative risks (95% confidence intervals) of 1.33 (1.10-1.62) and 2.85 (2.32-3.49), respectively, than in participants with normotension. In contrast, no significant differences were observed in the risk for stroke, cardiac outcomes or all-cause mortality. Our study suggests the importance of accurate and appropriate evaluation of WCH by utilizing out-of-office BP monitoring and the necessity for careful long-term follow-up of participants with WCH.