Source: Turner JR, et al. Am J Medicine 2015;128:14-20.
The benefits of hypertension treatment (HTN), often cited as a 25% reduction in myocardial infarction, 40% reduction in stroke, and 50% reduction in heart failure, have generally been demonstrated in clinical trials based on an office blood pressure measurement. Since a substantial minority of patients enrolled in HTN trials — approximately one-third according to numerous estimates — ultimately turn out to have white coat HTN (wc-HTN), we may be underestimating the actual benefits of HTN treatment. Patients with wc-HTN do not suffer the same increased risk of cardiovascular events as HTN patients; hence, their inclusion in HTN trials “dilutes” treatment effects.
Since 2011, the United Kingdom regulatory agency NICE (National Institute for Health and Care Excellence) has asked that primary care clinicians obtain ambulatory blood pressure monitoring (ABPM) on all patients suspected of HTN prior to initiation of treatment. Why? Because no treatment is indicated in the one-third of patients who typically turn out to have wc-HTN. United Kingdom calculations indicate that routine application of ABPM in primary care will save tens of millions of dollars.
ABPM is the most accurate tool for identifying wc-HTN. Additionally, it can help ascertain whether symptoms such as dizziness are potentially related to hypotensive episodes. It can also demonstrate whether treatment is truly providing 24-hour control of blood pressure, which is usually not discernible in typical office practice where patients are evaluated during daytime hours.
ABPM is a much better predictor of cardiovascular risk than office blood pressure readings. At the current time in the United States Medicare only pays for ABPM when the diagnosis of wc-HTN is utilized. Private insurance coverage for ABPM varies. More routine inclusion of ABPM would likely help to clarify important HTN-related issues.