Background: The long-term cardiovascular risk of isolated elevated office blood pressure (BP) is unclear.
Purpose: To summarize the risk for cardiovascular events and all-cause mortality associated with untreated white coat hypertension (WCH) and treated white coat effect (WCE).
Data sources: PubMed and EMBASE, without language restriction, from inception to December 2018.
Study selection: Observational studies with at least 3 years of follow-up evaluating the cardiovascular risk of WCH or WCE compared with normotension.
Data extraction: 2 investigators independently extracted study data and assessed study quality.
Data synthesis: 27 studies were included, comprising 25 786 participants with untreated WCH or treated WCE and 38 487 with normal BP followed for a mean of 3 to 19 years. Compared with normotension, untreated WCH was associated with an increased risk for cardiovascular events (hazard ratio [HR], 1.36 [95% CI, 1.03 to 2.00]), all-cause mortality (HR, 1.33 [CI, 1.07 to 1.67]), and cardiovascular mortality (HR, 2.09 [CI, 1.23 to 4.48]); the risk for WCH was attenuated in studies that included stroke in the definition of cardiovascular events (HR, 1.26 [CI, 1.00 to 1.54]). No significant association was found between treated WCE and cardiovascular events (HR, 1.12 [CI, 0.91 to 1.39]), all-cause mortality (HR, 1.11 [CI, 0.89 to 1.46]), or cardiovascular mortality (HR, 1.04 [CI, 0.65 to 1.66]). The findings persisted across several sensitivity analyses.
Limitation: Paucity of studies evaluating isolated cardiac outcomes or reporting participant race/ethnicity.
Conclusion: Untreated WCH, but not treated WCE, is associated with an increased risk for cardiovascular events and all-cause mortality. Out-of-office BP monitoring is critical in the diagnosis and management of hypertension.
Primary funding source: National Institutes of Health.