Masked hypertension associated with higher CV risk

Patients with masked hypertension — normal office BP, but high home BP — have a more than twofold risk for CV events compared with those with normal home and office BP, according to a new meta-analysis.

Results showed that home BP can refine risk stratification at office BP levels assumed to carry little to no risk, researchers wrote.

Finding masked hypertension

The researchers analyzed 5,008 participants (56.6% women; mean age, 57.1 years) randomly recruited from five studies. The participants were not taking antihypertensive medications and had BP readings that were taken in office and at home. Masked hypertension was defined as office systolic BP ≤140 mm Hg/diastolic BP ≤90 mm Hg, but a home BP of ≥130 mm Hg systolic/≥85 mm Hg diastolic. A home systolic BP threshold of ≥135 mm Hg also was used in sensitivity analyses.

Participants were followed for a median of 8.3 years. The primary outcome was first occurrence of any of the following: fatal and nonfatal stroke, fatal and nonfatal MI, death from ischemic heart disease, sudden death, fatal and nonfatal HF, surgical or percutaneous coronary revascularization, pacemaker implantation or other cardiac death.

During follow-up, 522 participants died, 414 had a CV event, 225 had a cardiac event and 194 had a cerebrovascular event, Kei Asayama, MD, PhD, of University of Leuven, Belgium, and colleagues found.

The HRs for a composite CV endpoint associated with a 10-mm Hg higher home systolic BP were as follows:

In participants with office systolic BP <120 mm Hg and diastolic BP <80 mm Hg: HR=1.28 (95% CI, 1.01-1.62).
In participants with office systolic BP between 120 mm Hg and 129 mm Hg and diastolic BP between 80 mm Hg and 84 mm Hg: HR=1.22 (95% CI, 1-1.49).
In participants with office systolic BP between 130 mm Hg and 139 mm Hg and diastolic BP between 85 mm Hg and 89 mm Hg: HR=1.24 (95% CI, 1.03-1.49); for stroke: HR=1.33 (95% CI, 1.07-1.65).
In participants with office systolic BP between 140 mm Hg and 159 mm Hg and diastolic BP between 90 mm Hg and 99 mm Hg: HR=1.2 (95% CI, 1.06-1.37); for stroke: HR=1.3 (95% CI, 1.09-1.56).

There was no effect in patients with office systolic BP ≥160 mm Hg and diastolic BP ≥100 mm Hg, the researchers found.

Among those with office systolic BP <120 mm Hg and diastolic BP <80 mm Hg, 5% had masked hypertension; among those with office systolic BP between 120 mm Hg and 129 mm Hg and diastolic BP between 80 mm Hg and 84 mm Hg, 18.4% had masked hypertension; and among patients with office systolic BP between 130 mm Hg and 139 mm Hg and diastolic BP between 85 mm Hg and 89 mm Hg, 30.4% had masked hypertension.

For those with office systolic BP ≤139 mm Hg and diastolic BP ≤89 mm Hg, masked hypertension was associated with a 2.3-fold (95% CI, 1.5-3.4) higher CV risk.

“Our study identified a novel indication for [home BP], which, in view of its low cost and the increased availability of electronic communication, might be globally applicable, even in remote areas or in low-resource settings,” Asayama and colleagues wrote.

No comparison with ambulatory BP

In a related editorial, Mark Caulfield, MD, of Queen Mary University of London, wrote that although the findings make a good case for home BP monitoring, they do not compare home BP monitoring with ambulatory BP monitoring, which a 2011 United Kingdom guideline states is superior.

A head-to-head comparison “would be valuable in assessing whether [home BP monitoring] could be of sufficient diagnostic and prognostic precision to replace [ambulatory BP monitoring] in the confirmation of a diagnosis informing a decision to treat,” Caulfield wrote.

For more information:

Asayama K. PLoS Med. 2014;doi:10.1371/journal.pmed.1001591.

Caulfield M. PLoS Med. 2014;doi:10.1371/journal.pmed.1001592.

Disclosure: The researchers and Caulfield report no relevant financial disclosures.