Automated office BP (AOBP) lessens some of the limitations inherent with the traditional sphygmomanometer auscultatory and single-measurement oscillometric devices. AOBP combines oscillometric technology with the capacity to record multiple BP readings within a single activation, thereby providing an average of these readings.1 The total time required for AOBP is 4 to 6 minutes, including a brief rest period before the measurement starts. Studies have reported comparable readings between staff-attended and unattended AOBP, which is an encouraging way to eliminate some measurement error (eg, talking with the patient) and to improve efficiency.5,6
Waiting several minutes per patient to record BP may not be practical in a busy office setting and may require an alteration of workflow. There is a paucity of literature evaluating practice realities, which makes it difficult to know how many patients are getting their BP checked in this manner. Several studies have shown that BP measured with AOBP is closer to awake out-of-office BP as measured with ABPM (discussed in a bit),5-8 largely through mitigation of white-coat effect. Canada now recommends AOBP as the preferred method for diagnosing HTN and monitoring BP.9
Home blood pressure monitoring
HBPM refers to individuals measuring their own BP at home. It is important to remember this definition, as the term is sometimes applied to a patient’s BP measured at home by an observer or to an individual taking their own BP outside of the home (kiosk, pharmacy, at work). The short-term reproducibility of mean BP with HBPM is high. The test-retest correlations of HBPM range from 0.70 to 0.84 mm Hg for mean SBP, and from 0.57 to 0.83 mm Hg for mean DBP.10-13 In contrast to 24-hour ABPM, HBPM is better tolerated, cheaper, and more widely available.14,15
There is strong evidence that HBPM adds value over and above office measurements in predicting end-organ damage and cardiovascular disease (CVD) outcomes, and it has a stronger relationship with CVD risk than office BP.1 Compared with office BP measurement, HBPM is a better predictor of echocardiographic left ventricular mass index, urinary albumin-to-creatinine ratio, proteinuria, silent cerebrovascular disease, nonfatal cardiovascular outcomes, cardiovascular mortality, and all-cause mortality.15,16 There is no strong evidence demonstrating the superiority of HBPM over ABPM, or vice versa, for predicting CVD events or mortality.17 Both ABPM and HBPM have important roles in out-of-office monitoring (FIGURE 23).
Clinical indications for HBPM
HBPM can facilitate diagnosis of white-coat HTN or effect (if already on BP-lowering medication) as well as masked uncontrolled HTN and masked HTN. Importantly, masked HTN is associated with nearly the same risk of target organ damage and cardiovascular events as sustained HTN. In one meta-analysis the overall adjusted hazard ratio for CVD events was 2.00 (95% CI, 1.58-2.52) for masked HTN and 2.28 (95% CI, 1.87-2.78) for sustained HTN, compared with normotensive individuals.18 Other studies support these results, demonstrating that masked HTN confers risk similar to sustained HTN.19,20
Even treated subjects with masked uncontrolled HTN (normal office and high home BP) have higher CVD risk, likely due to undertreatment given lower BP in the office setting. Among 1451 treated patients in a large cohort study who were followed for a median of 8.3 years, CVD was higher in those with masked uncontrolled HTN (adjusted hazard ratio = 1.76; 95% CI, 1.23-2.53) compared to treated controlled patients (normal office and home BP).21
Home BP monitoring can reveal masked hypertension, which confers risk for endorgan damage similar to that of sustained hypertension.
HBPM also can be used to monitor BP levels over time, to increase patient involvement in chronic disease management, and to improve adherence with medications. Since 2008, several meta-analyses have been published showing improved BP control when HBPM is combined with other interventions and patient education.22-25 Particularly relevant in the age of increased telehealth, several meta-analyses demonstrate improvement in BP control when HBPM is combined with web- or phone-based support, systematic medication titration, patient education, and provider counseling.22-25 A comprehensive systematic review found HBPM with this kind of ongoing support (compared with usual care) led to clinic SBP reductions of 3.2 mm Hg (95% CI, 1.6-4.9) at 12 months.22
