Ambulatory BP monitoring deemed cost-effective in most scenarios

Ambulatory blood pressure monitoring (ABPM) is cost-saving across nearly all age groups, regardless of whether patients are found to have hypertension on the initial screening, according to a study published in Hypertension.

Hadi Beyhaghi, MD, PhD, and Anthony J. Viera, MD, MPH, sought to compare the lifetime costs and quality-adjusted life-years (QALY) for the three main diagnostic strategies for high blood pressure. These include clinic BP measurements; home BP monitoring, in which multiple measurements are taken by a patient during a week; and ABPM, where measurements are taken automatically during a 24-hour span.

Clinic BP readings are used most commonly in practice, but the other methods are more effective at detecting white-coat hypertension (false positives in the clinic) and masked hypertension (false negatives in the clinic). However, ABPM and home BP monitoring (HBPM) are more costly, tougher to implement and only partially reimbursed by insurance, contributing to their limited uptake.

Beyhaghi and Viera said their cost-effectiveness analysis is the first to compare these three strategies among both old and young adults, ranging from 21 to 80 years old, while also accounting for the possibilities of masked and white-coat hypertension.

They found ABPM was the dominant strategy across all age groups when the initial screening was positive for hypertension—at least 140/90 mm Hg in this study—with lifetime savings versus clinic BP measurements ranging from $77 for the average 80-year-old woman to $5,013 for the average 21-year-old woman. Lifetime costs were calculated from the U.S. healthcare payer perspective and estimated out to age 85 for each individual, meaning follow-up ranged from five to 64 years depending on the group being studied.

Lifetime cost savings for men who initially screened positive for hypertension ranged from $147 at age 80 to $4,671 at age 21 with ABPM instead of clinic measurements. HBPM was the most expensive of all the strategies across age groups.

When patients didn’t initially have hypertension, ABPM was associated with cost savings for all patients 70 or younger—ranging from $128 for 70-year-old women to $2,794 for 21-year-old women. For 80-year-olds of both sexes, clinic readings were most cost-effective.

“Overall, the findings of this study suggest that using ABPM is the strategy of choice for hypertension diagnosis and treatment initiation for most adults in primary care settings,” wrote Beyhaghi, with the University of North Carolina; and Viera, with Duke University. “We predict that correctly diagnosing white-coat and masked hypertension by ABPM reduces the overall cost of treatment for hypertension and future cardiovascular disease events.”

The authors used a hypothetical study cohort of primary care patients who matched the general U.S. population in terms of cardiovascular risk factors. They used previously published data to inform their calculations of costs related to antihypertensive medications, hospital stays associated with specific events and maintenance costs related to coronary heart disease or cerebrovascular disease. The Framingham risk equations were used to determine age- and sex-specific probabilities of cardiovascular and cerebrovascular events occurring in both hypertensive and normotensive patients.

To model these events and costs in the hypothetical population, Beyhaghi and Viera also assumed that patients with masked hypertension would receive the same benefit from antihypertensive treatment as regular hypertensive patients, and that these medications would be equally protective against all cardiovascular events.

With these assumptions, they calculated ABPM would result in a marginal increase in quality-adjusted days of life in most age groups. Hypertensive 21-year-old women had the greatest longevity gains (28.6 quality days) with ABPM over clinic BP monitoring.

“Our findings have policy significance in the sense that expanding the reimbursement of ABPM as a diagnostic strategy for hypertension in primary care settings may reduce healthcare costs and improve health outcomes by getting hypertension treatment to the correct patients,” the authors wrote.

The U.S. Preventive Services Task Force in 2015 gave a grade A recommendation for out-of-office BP measurements to confirm a diagnosis of hypertension before starting treatment.

Citing this recommendation, the American Heart Association and American Medical Association authored a joint letter to CMS in May asking the agency to consider expanding the scope of its reimbursement policies for ABPM, which is currently only covered when strict criteria for white-coat hypertension are met.

CMS already solicited public comments on its new National Coverage Determination for ABPM, which is expected to be announced next April.