番茄社区

Ambulatory blood pressure monitoring is the most cost-effective way to confirm a hypertension diagnosis before starting treatment, researchers found.

The cost-savings from avoiding misdiagnosis was greater with ambulatory monitoring than with further blood pressure measurements in the office or at home, Richard J. McManus, MSc, MBBS, of the University of Birmingham, England, and colleagues reported.

Ambulatory confirmation saved from $92 (£56) to $533 (£323) across groups in the modeling study released online in The Lancet.

Moreover, ambulatory monitoring slightly boosted quality-adjusted life years among patients older than 50.

"Ambulatory monitoring for most people before the start of antihypertensive treatment should be seriously considered," McManus' group argued in the paper.

In response, the British regulatory agency that helped fund the study is altering its guidelines to recommend ambulatory monitoring as a best practice.

The National Institute for Health and Clinical Excellence (NICE) announced the change at a press briefing held in London the same day as the Lancet paper was published.

The American Heart Association recommends home monitoring for newly diagnosed or suspected hypertension with ambulatory monitoring reserved for equivocal cases to help establish the diagnosis.

The traditional approach has been two repeat visits for in-office measurement after an initial finding of elevated blood pressure, Thomas A. Gaziano, MD, of Brigham and Women's Hospital in Boston, noted in a commentary accompanying the Lancet study.

That ambulatory monitoring is cost-saving isn't surprising because it addresses the problem of white-coat hypertension, he pointed out.

"Improved diagnosis by both home and ambulatory monitoring results in reduction of morbid or fatal, as well as expensive, events attributable to cardiovascular disease, and minimizes treatment of people who otherwise would be incorrectly labelled hypertensive," Gaziano wrote in the commentary.

The financial savings with ambulatory monitoring compared with home monitoring was likely because the automated ambulatory monitoring device has greater accuracy, suggested Joseph Diamond, MD, director of nuclear cardiology at Long Island Jewish Medical Center in Hyde Park, N.Y.

Whether serially-obtained automated blood pressure measurements could be just as accurate and cost-effective if taken in the office isn't clear, he noted in a statement sent to reporters.

McManus' group modeled cost-effectiveness on a hypothetical primary-care population age 40 and older that screened positive for a blood pressure over 140/90 mm Hg and had hypertension risk factor prevalence similar to the general population.

After accounting for costs associated with equipment, consumables, maintenance, and staff time as well as costs of treatment for hypertension and cardiovascular events, ambulatory monitoring for 24 hours to confirm hypertension diagnosis was less expensive in all gender and age groups than several repeat office visits or home measurements over a week's time.

These savings "were primarily because of the costs of hypertensive treatment that were avoided because of the higher specificity of ambulatory monitoring," the researchers noted.

They pointed to the example of 60-year-old men for whom ambulatory monitoring cost $69 (£42) more per diagnosis but saved $237 (£144) in treatment costs compared with clinic monitoring, while costs for subsequent cardiovascular events and follow-up were similar between groups.

Home monitoring had similar results as office visits for both quality of life and costs across age and gender groups.

Even in the younger age groups for whom ambulatory monitoring was associated with a small reduction in quality-adjusted life years and cost-effectiveness ratios greater than $82,470 (£50,000) per QALY, it remained most cost effective.

The only assumptions that changed the ranking of the three methods were if home monitoring was as accurate as ambulatory testing and if treating people who did not have true hypertension actually reduced their cardiovascular risk.

If repeat screening was done on a yearly rather than every-five-year basis for those who screened negative for hypertension, home monitoring became more cost-effective for younger age groups, although "unrealistic in clinical practice where annual ambulatory monitoring would be judged excessive for most people."

The researchers noted that if they had included small negative effects of treatment side effects in their analysis, the cost-effectiveness of ambulatory monitoring would have looked even better.

The results are likely widely generalizable to primary care, they added, pointing to prior studies from the U.S., Australia, and Italy that found cost savings with ambulatory rather than further in-office monitoring.

Comment