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Ambulatory BP monitoring a better mortality predictor than clinic BP

By Nicole MacKee
Ambulatory blood pressure (ABP) monitoring is a more reliable predictor of all-cause and cardiovascular (CV) mortality than clinic readings, according to Spanish research published in The New England Journal of Medicine.

The study found that 24-hour systolic BP was more strongly associated with all-cause mortality (hazard ratio [HR], 1.58 per one standard deviation increase in BP) than clinic systolic BP (HR, 1.02). The registry-based, cohort study followed 63,910 adults for a median of 4.7 years. Participants had ABP monitoring to evaluate white-coat hypertension, resistant hypertension or high-risk hypertension.

Masked hypertension was associated with the greatest all-cause mortality risk (HR, 2.83), while increased risk was also found with sustained hypertension (HR, 1.80) and white-coat hypertension (HR, 1.79). Similar findings were reported for CV mortality.

Professor Mark Nelson, Chair of General Practice at the University of Tasmania, said while the findings confirmed ABP monitoring as the gold standard measurement tool, it remained out of reach for general practice.

‘Ambulatory blood pressure monitoring machines are expensive, and the procedure is not rebated under Medicare,’ said Professor Nelson, who is also Clinical Liaison for the High Blood Pressure Research Council of Australia.

Home monitoring was a good alternative to ambulatory monitoring, he said, adding that materials to support patients, such as data diaries, could be downloaded from The Heart Foundation’s website. Automated clinic readings were also a good option in general practice, he told Cardiology Today.

Professor Nelson said concerns about under- or overtreatment of hypertension could also be addressed by retiring the term ‘hypertension’ and focusing on absolute risk scores.

‘Decisions to prescribe blood pressure medications should be made holistically on the basis of a person’s absolute risk of having a heart attack or stroke over the next five years,’ he said. ‘When absolute risk is used, the effects of measurement error are moderated, because blood pressure is one of several components in the decision to use blood pressure medication.’
N Engl J Med 2018; 378: 1509-1520.