Patients with untreated white coat hypertension twice as likely to die of CVD

Heart patients with untreated white coat hypertension (WCH) are more than twice as likely to die from cardiovascular disease as their normotensive counterparts, according to a June 11 study.

The research, funded by the National Institutes of Health and published in the Annals of Internal Medicine, analyzed the relationship between adverse CV events and patients with both untreated WCH and treated white coat effect (WCE), a condition in which patients receive antihypertensive treatment for their WCH. Despite recent guidelines encouraging more out-of-office and ambulatory BP monitoring, first author Jordana B. Cohen, MD, MSCE, and colleagues said hypertension is still most often diagnosed in the doctor’s office.

“The clinical inertia surrounding out-of-office BP monitoring seems to be driven by several provider-, patient- and policy-related factors,” Cohen, a physician at Penn Medicine, and co-authors wrote in the journal. “A major barrier is skepticism over the utility of screening for isolated office hypertension due to unclear evidence.”

Cohen et al. strove for more clarity in their study of more than 25,000 WCH patients, combing the PubMed and EMBASE databases for relevant observational studies with at least three years of follow-up. They ultimately included 27 studies in their analysis, comprising a total 25,786 patients with untreated WCH or treated WCE and 38,487 normotensive patients.

Subjects were followed for between 3 and 19 years. Compared to patients with normal BP, those with untreated WCH saw a 36% increased risk for cardiovascular events and a 33% increased risk for all-cause mortality, as well as a more than twofold increased risk of CV death.

The risk of WCH lessened in studies that also included stroke in the definition of cardiovascular events, Cohen and colleagues reported. There was no significant link between treated WCE and cardiovascular events, all-cause mortality or CV death, and the authors said their findings persisted across multiple sensitivity analyses.

In a separate editorial, Diachi Shimbo, MD, of Columbia University Medical Center, and Paul Muntner, PhD, of the University of Alabama at Birmingham, applauded the team’s work for its strengths—the researchers conducted a thorough literature review, included recent studies and limited their scope to trials that adjusted for potential confounders—but said it also has some limitations.

Although Cohen et al.’s results were consistent across most subgroup analyses, Shimbo and Muntner said, the association between WCH and CVD risk was present only in studies where participants were at least 55 years old and those in which patients had a history of CVD, chronic kidney disease or diabetes. That weakens the link, suggesting the increased risk that comes with untreated WCH might only apply to older populations who are already at a high risk for CVD.

“For adults taking antihypertensive medication, the results are clear,” the editorialists wrote. “White coat effect is not associated with increased risk, and out-of-office monitoring seems warranted to prevent intensification of antihypertensive treatment. For adults not taking antihypertensive medication, the risk for CVD events and all-cause mortality is only moderately increased, and this risk is substantially lower than that associated with sustained hypertension.”

Therefore, they said, out-of-office monitoring is useful for distinguishing between WCH and sustained hypertension in patients with high in-office BP readings. In their study, Cohen and her co-authors said their results will hopefully move out-of-office BP monitoring forward as a standard of care.

“Overall, the meta-analysis by Cohen and colleagues makes an important contribution and provides contemporary data supporting recent U.S. and European guidelines that recommend out-of-office BP monitoring to screen for WCH and WCE,” Shimbo and Muntner wrote.