Bringing the Cuff Home: Challenges and Opportunities Associated With Home Blood Pressure Monitoring Among Reproductive-Aged Individuals

Hypertension is one of the most common and important modifiable risk factors for cardiovascular disease (CVD), yet the proportion of individuals achieving blood pressure (BP) control in the United States is declining. Among women, hypertension contributes to more than one-third of CVD-related mortality.¹ Elevated BP is present by young adulthood and hypertension (BP ≥130/80 mm Hg) affects 13.6% of 20–34 year olds and 30.3% of 35–44 year olds among women.¹ Optimizing BP is of particular importance during the reproductive years given that prepregnancy hypertension is associated with increased risk of both adverse maternal and fetal outcomes, including superimposed preeclampsia, preterm birth, and fetal growth restriction.² Additionally, new-onset hypertension that develops during pregnancy (gestational hypertension/preeclampsia) is a leading risk factor for 12%–16% of maternal deaths, and is associated with a 2-fold higher lifetime CVD risk in birthing individuals.^3–5 Therefore, controlling BP after hypertensive disorders of pregnancy, during the interconception period, is critical to reducing risk of adverse pregnancy outcomes during subsequent pregnancies, as well as long-term CVD risk among reproductive-aged women. Yet, less than one-quarter of women in the United States achieve recommended levels of BP control.¹

Home blood pressure monitoring (HBPM) is recognized by the 2017 American College of Cardiology (ACC) and American Heart Association (AHA) Guidelines for Hypertension as an important adjunct to in-office diagnosis and for monitoring response to treatment of hypertension.^6,7 The guidelines also recommend ambulatory BP monitoring, which involves an automated monitoring device worn over a 24-hour period when white coat hypertension or masked hypertension is suspected. However, this can be cumbersome, poorly tolerated, and often hard to access. Therefore, patient-centered self-measurement of BP at home is a more feasible and practical alternative. However, little is known about how many reproductive-aged women with hypertension are counseled on measuring their BP at home and how many use HBPM.

In this issue of American Journal of Hypertension, Kovell et al.⁸ describe a cross-sectional analysis to address this question in the National Health and Nutrition Examination Survey from 2009 to 2014 (the only years when participants were asked about checking BP at home). Among 2,872 reproductive-aged women (representing 40 million), 8.7% or 250 self-reported a diagnosis of hypertension. Among those who reported hypertension, 72% had obesity, 16% diabetes, and 7% CVD. Of those who reported hypertension, approximately half endorsed measuring their BP at home in the last 12 months and 40% reported they were advised by a clinician to monitor BPs at home. Differences in self-report of HBPM differed by education level with higher use among those with at least some college education (odds ratio = 1.43 [95% confidence interval 1.03–2.0]), which may also be a proxy for health literacy, healthcare access, and other socioeconomic factors.

Kovell et al.’s study is strengthened by use of a national dataset that is representative of reproductive-aged women living in the United States. Key limitations, as noted by the authors, include the historical sample prior to the release of the 2017 guidelines, lack of precise information on frequency of monitoring (reported times were averaged over 52 weeks), and potential for inaccurate use of HBPM (i.e., use of validated cuffs, appropriate measurement techniques). There were also insufficient sample sizes (n < 10) to reliably determine rates of HBPM use among pregnant individuals. However, by providing national estimates of HBPM counseling and use among reproductive-aged individuals, the study raises several important questions regarding the implementation gap in integrating HBPM in the United States in this subset of reproductive-aged women and the potential reasons for low rates of HBPM between 2009 and 2014.

First, what is driving low rates of HBPM? Less than half of reproductive-aged women with hypertension in this sample reported measuring their BP at home, though it should be noted these survey responses were prior to the 2017 guideline, which reemphasized use of out-of-office BP monitoring. One potential driver for low uptake of HBPM use, as suggested by Kovell et al., is a lack of counseling by clinicians. In the present study, only 40% of patients recalled counseling from a clinician on HBPM. However, it is possible that recall bias may play a role in these responses. Further, access to healthcare or having a regular primary care clinician may be drivers of lack of counseling. On the health system side, potential barriers may include concerns regarding time required to instruct patients on proper BP cuff use, accuracy of HBPM, and reimbursement for out-of-office monitoring. From a patient perspective, there may be apprehension regarding cost of equipment, comfort with technology, and data privacy.⁹ To improve rates of BP control, we must identify who would benefit from HBPM, how to implement use of HBPM, and how to effectively communicate and adjust treatment in response to HBPM. Systems-based reforms are needed to provide reimbursement for clinician time, equipment, and resources that incorporate patient-centered, culturally tailored materials with appropriate levels of health literacy. Further, the development of integrated and secure data sharing platforms that also have the potential to leverage artificial intelligence methods to synthesize data minimize clinician burden of reviewing potentially hundreds of BP values may improve uptake and effectiveness of HBPM. Ensuring that validated BP monitors are easily accessible, affordable, and covered by health insurance will also be key to the equitable dissemination of remote monitoring.

If these systems are put in place, then what are the specific opportunities for HBPM use among reproductive-aged women? Pregnancy is a hallmark event in this period of the life course and represents a particularly vulnerable time during which the cardiovascular system undergoes dramatic hemodynamic adaptations in order to meet the metabolic demands of fetal growth and development.¹⁰ Controlling BP before and during pregnancy is critical for promoting a safe pregnancy for mother and child. Recent data from the Chronic Hypertension and Pregnancy (CHAP) Trial demonstrated lowering BP to <140/90 (compared with 160/110) during pregnancy resulted in lower rates of severe preeclampsia and medically induced preterm birth among pregnant individuals with prepregnancy hypertension. As a result, the American College of Obstetricians and Gynecologists revised their guidelines to recommend initiating and titrating antihypertensives to achieve a goal BP of <140/90 (instead of <160/110) for individuals with prepregnancy hypertension.^11,12 Continued, close BP monitoring postpartum remains critical given that 60% of maternal deaths from hypertension occur within 45 days following delivery.³ The postpartum period also represents a unique opportunity during which hypertension and other CVD risk factors can be optimized prior to the next pregnancy. Among reproductive-aged women with hypertension in Kovell et al.’s study, over 70% had obesity and 16% had diabetes, representing a group that could substantially benefit from intensive risk factor optimization in the form of lifestyle and medical interventions during this interconception period. Unfortunately, less than 60% of individuals with a hypertensive disorder of pregnancy follow-up with a clinician after pregnancy.¹³

Use of HBPM has the potential to not only enhance detection and monitoring of hypertensive disorders of pregnancy, but also bridge this gap in postpartum care by increasing accessibility and convenience for new mothers. In a recent meta-analysis, HBPM during the antenatal period was associated with higher rates of detection of preeclampsia, as well as lower risk of induction of labor and prenatal hospitalizations, while requiring less antenatal clinic visits.¹⁴ However, there was substantial methodologic heterogeneity among the included studies in this analysis, as well as inconsistent use of BP cuffs validated in pregnancy.¹⁵ The Blood Pressure Monitoring in High Risk Pregnancy to Improve Detection and Monitoring of Hypertension (BUMP) trial provides some of the most reliable data on HBPM in pregnancy to-date.^16,17 Although use of HBPM in addition to usual care in the BUMP trial was not associated with earlier clinic-based detection of hypertension among those at higher risk of preeclampsia nor lower BPs among those with chronic or gestational hypertension living in the United Kingdom, the generalizability of these findings to pregnant individuals in the United States is unclear given country-based differences in healthcare policy, practice, and accessibility.

So what needs to be done to best use HBPM in reproductive-aged and pregnant individuals to improve CVD outcomes? First, we need to better quantify rates of clinician counseling and successful integration of HBPM after the release of the 2017 ACC/AHA Hypertension Guidelines, as well as during the Coronavirus-19 Pandemic when remote monitoring has become increasingly important. We also need to understand these rates during different periods of the life course, particularly before, during, and after pregnancy. To date, few studies have successfully engaged women from prepregnancy through postpartum. Second, we must identify root causes for low rates of counseling and HBPM use. Third, we need to develop educational content and train patients in proper HBPM techniques with use of validated and calibrated devices. Fourth, we must develop methods for practical implementation of HBPM in the clinical setting, and strategies to adjust BP treatment in response to HBPM data, as achieving BP control requires both accurate monitoring and prompt response to adjust and titrate pharmacotherapies. Lastly, we must work with communities, researchers, and policy makers to ensure equitable and universal access to accurate BP devices among reproductive-aged and pregnant individuals in the United States.

FUNDING

This work was supported by grants from the National Heart, Lung and Blood Institute (1R01HL161514) to Sadiya S. Khan. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Natalie A. Cameron is supported by the Northwestern University Feinberg School of Medicine Division of General Internal Medicine and Geriatrics Research Fellowship.

DISCLOSURE

The authors declared no conflict of interest.