The Continuing Challenge of Low Rates of Blood Pressure Control Among US Adults

The US National Health and Nutrition Examination Survey (NHANES) has provided data on hypertension awareness, treatment, and control among US adults for more than 50 years.1 NHANES participants are selected using a multistage sampling approach which allows the results to be weighted to represent the noninstitutionalized US population. Data, including blood pressure (BP) measurements and information on antihypertensive medication, are collected following rigorous, standardized protocols by trained study staff. Previous analyses of NHANES data have indicated a marked increase in the proportion of US adults with hypertension for several decades. For example, the proportion of US adults with hypertension that had controlled BP, systolic BP (SBP) <140 mm Hg and diastolic BP (DBP) <90 mm Hg, increased from 31.8% in 1999–2000 to 53.8% in 2013–2014.2 However, an analysis of NHANES data published in 2020 indicated that the improvement in BP control was reversed between 2013–2014 and 2017–2018. According to NHANES 2017–2018, 43.7% of US adults with hypertension had controlled BP.2 Estimates of the proportion of US adults with hypertension with controlled BP were recently updated with more contemporary NHANES data.3 NHANES stopped their 2019–2020 cycle in March 2020 due to the COVID-19 pandemic. While data were not complete for producing estimates for the US noninstitutionalized population in 2019–2020, the data can be pooled with the NHANES 2017–2018 data to produce estimates for the US population from January 2017 through March 2020.4 Using data from NHANES from 2009 through March 2020, trends in BP control among US adults with hypertension were updated and the proportion of US adults with hypertension that had controlled BP declined from 52.8% (95% confidence interval [CI] 50.0%–55.7%) in 2009–2012 to 51.3% (95% CI 47.9%–54.6%) in 2013–2016 to 48.2% (95% CI 45.7%–50.8%) in 2017–2020.3 A decline in BP control occurred over this time period in several subgroups including US adults ≥75 years, women and non-Hispanic Black adults. While the decline in BP control among US adults with hypertension reporting using the most contemporary NHANES data is not as striking as the NHANES 2017–2018 suggested, the updated results raise several concerns. First, fewer than 50% of US adults with hypertension had controlled BP. Among US adults taking antihypertensive medication, less than 70% had controlled BP. Second, a marked decline in BP control was present in several vulnerable populations including US adults ≥75 years of age, non-Hispanic Black adults and women. These data emphasize the need to ensure all populations have the opportunity to be adequately treated with antihypertensive medication. Third, fewer than 25% of US adults with hypertension had controlled BP when defined by the 2017 ACC/AHA guideline recommendations, SBP/DBP <130/80 mm Hg.5 These recent NHANES data provide information on the state of BP control among US adults.3 However, many questions remain unanswered including why BP control has declined among US adults and what can be done to reverse the trends in declining BP control. While the exact reasons for the decrease in BP control are unclear, a variety of barriers and facilitators to BP control have been reported. Below we describe potential reasons why BP control has declined among US adults with hypertension and approaches to address them. In December 2013, the panel members appointed to eighth Joint National Committee (JNC8) published a report that recommended higher BP goals for some adults compared with the previous US guideline, the seventh Joint National Committee (JNC7) guideline.6,7 At the time the JNC8 panel member report was published, some members raised concern that the higher BP goals would result in less intense antihypertensive treatment and a higher proportion of US adults with uncontrolled BP.8 The 2017 ACC/AHA BP guideline was published in November 2017 and has lower BP goals than the JNC7 guideline and JNC8 panel member report.5 It is unclear to what extent the recommendations in the JNC8 panel member report were implemented and whether the 2017 ACC/AHA BP guideline is being implemented. However, only 48% of US adults with hypertension had controlled BP in 2017–2020, a period mostly after publication of the 2017 ACC/AHA BP guideline.3 Efforts are needed to implement the 2017 ACC/AHA BP guideline as this may result in improved BP control among US adults. It is well known that most patients with hypertension require 2 or more classes of antihypertensive medication to control their BP.9 Initiating antihypertensive medication combination therapy lowers BP more than monotherapy.10,11 In a meta-analysis of 33 trials (n = 13,095), combination therapy with 2 drugs of less than standard dosage, 1 drug at standard dosage and 1 drug at less than standard dosage and 2 drugs at standard dosages, reduced SBP by 2.8 (95% CI 1.6–4.0), 4.6 (95% CI 3.4–5.7), and 7.5 (95% CI 5.4–9.5) mm Hg more than antihypertensive monotherapy, respectively.11 Additionally, the risk ratio for controlled BP, SBP <140 mm Hg and DBP <90 mm Hg, was 1.11 (95% CI 0.92–1.34), 1.25 (95% CI 1.16–1.35), and 1.42 (95% CI 1.27–1.58) for those randomized to combination therapy with 2 drugs at less than standard dosages, 1 drug at standard dosage and 1 drug at less than standard dosage and 2 drugs at standard dosages vs. monotherapy, respectively. The 2017 ACC/AHA BP guideline recommends that adults with SBP ≥140 mm Hg or DBP ≥90 mm Hg initiate antihypertensive medication with combination therapy.5 Despite data from multiple randomized trials and guideline recommendations, many US adults do not receive antihypertensive medication with combination therapy. According to NHANES 2013–2016, 40.2% of US adults with uncontrolled BP, SBP ≥140 mm Hg or DBP ≥90 mm Hg, were taking a single drug class.12 Initiating antihypertensive medication with combination therapy may be an effective approach to improve BP control among US adults. More frequent interaction between patients and their healthcare providers may be an important approach to facilitate BP control. In NHANES 2013–2018, 7% of US adults with hypertension reported not having a healthcare visit in the past year and this was the strongest risk factor for uncontrolled BP.13 Also, US adults without vs. with a healthcare visit in the past year were less likely to be aware they had hypertension (45.0% vs. 83.9%), to be taking antihypertensive medication among those who were aware they had hypertension (36.7% vs. 91.4%) and to have SBP <140 mm Hg and DBP <90 mm Hg (9.1% vs. 51.7%). Multiple initiatives have recognized the importance of regular healthcare visits as an approach to improve BP control including the Million Hearts Hypertension Control Champions of the Centers for Disease Control and the Centers for Medicare and Medicaid Services Million Heart initiative. Also, the 2020 US Surgeon General’s Call to Action to Control Hypertension emphasized the need for early and consistent access to healthcare to improve BP control.14 Providing BP checks without copayments and ensuring patients have a usual place to receive healthcare may facilitate more frequent monitoring of BP leading to opportunities to intensify medication, leading to BP control. Self-measured BP monitoring (SMBP) refers to the measurement of BP by an individual outside of an office setting at their home.15 SMBP alone is not effective in lowering BP.16 However, with cointerventions including telecounseling or education, SMBP lowers SBP and DBP and improves BP control.16 However, SMBP remains under-utilized among US adults with hypertension.17 The World Health Organization defines the social determinants of health as “the conditions in which people live, learn, work, play, worship, and age.” 18 The social determinants of health can be grouped into 5 domains: (i) Economic Stability, (ii) Education, (iii) Health and Health Care, (iv) Neighborhood and Built Environment, and (v) Social and Community Context.19 Studies have identified adverse social determinants of health to be associated with worse BP control.20 The Centers for Medicare and Medicaid Services developed the Accountable Health Communities Health-Related Social Needs Screening Tool to assess if detecting and addressing health-related social needs effects total healthcare costs and improves health outcomes. Additionally, recommendations to assess and address social determinants are provided in the 2019 ACC/AHA Performance Measures for Adults with High Blood Pressure.21 Creating health equity is a priority for many organizations and may be a useful approach for improving BP control among US adults. In conclusion, NHANES data provide important information on the health of the US population and the NHANES 2017–2020 indicate a large gap in care for US adults with hypertension. A recent compendium in the American Journal of Hypertension provides an overview of the US Surgeon General’s report to Control Hypertension, detailed approaches that can be used to facilitate BP control and a review of the importance of improving BP control in the United States.22–27 Dedicated efforts from researchers, clinicians, policy makers, and public health professionals are needed to ensure all US adults are enabled to prevent hypertension, receive guideline recommended treatment and control BP to levels demonstrated to reduce cardiovascular disease risk. Until this happens, hypertension and uncontrolled BP are going to remain common among US adults, leading to the occurrence of preventable cardiovascular disease events. The author declared no conflict of interest.