The prevalence and control of hypertension in adults

INTRODUCTION — Hypertension is a highly prevalent disease and rates of control are suboptimal. The definition of hypertension and indications for treatment have changed, and such changes have impacted these statistics. (See "Overview of hypertension in adults", section on 'Definitions' and "Overview of hypertension in adults", section on 'Making the diagnosis of hypertension' and "Overview of hypertension in adults", section on 'Treatment'.)

This topic will discuss both the prevalence and control of hypertension in adults. The evaluation of hypertension, management, and treatment goals are presented elsewhere. (See "Blood pressure measurement in the diagnosis and management of hypertension in adults" and "Initial evaluation of adults with hypertension" and "Choice of drug therapy in primary (essential) hypertension" and "Goal blood pressure in adults with hypertension".)

PREVALENCE OF HYPERTENSION — The prevalence of hypertension depends upon the definition of hypertension. In 2017, the American College of Cardiology/American Heart Association (ACC/AHA) lowered the threshold for the definition of hypertension [1]. The prevalence data presented below should be interpreted according to the definition of hypertension at the time the study was done unless otherwise stated. (See "Overview of hypertension in adults", section on 'Definitions'.)

The United States National Health and Nutrition Examination Surveys (NHANES) have provided epidemiologic information on the prevalence and control of hypertension in the United States [2-11]. Prior to the redefinition of hypertension by the 2017 ACC/AHA guidelines, the prevalence of hypertension in the United States (defined as taking antihypertensive medication or having a systolic pressure of ≥140 mmHg and/or a diastolic pressure ≥90 mmHg) was approximately 30 percent and had remained relatively constant since 1999 [1,2,7-9].

Substantially more people have hypertension using the ACC/AHA definition (ie, taking antihypertensive medication or having a systolic pressure ≥130 mmHg and/or a diastolic pressure ≥80 mmHg). Applying this definition to NHANES data, the prevalence of hypertension among adults age 18 and older in the United States was 47 percent from 1999 to 2000, 41.7 percent from 2013 to 2014, and 45.4 percent from 2017 to 2018 (figure 1) [12]. If hypertension had been defined as taking antihypertensive medication or having a blood pressure ≥140 mmHg systolic or ≥90 mmHg diastolic, approximately 31 percent of adults in the United States would have been classified as having hypertension from 2017 to 2018.

In the United States, the prevalence of hypertension is higher among males, older adults, Black adults, those with obesity, chronic kidney disease, diabetes, and those living in rural areas [3-9,12,13]. The disparity in hypertension prevalence between older and younger adults, and between Black adults and other adults narrowed after the definition was changed by the 2017 guidelines [2].

The global prevalence of hypertension is similar to that in the United States, although it varies by country [14-17]. Using a definition of hypertension of taking antihypertensive medication or having a blood pressure ≥140 mmHg systolic or ≥90 mmHg diastolic, pooled data suggest that, in 1990, approximately 32 percent of the world's adult population (aged 30 to 79 years) had hypertension [17]. In 2019, the estimated global prevalence remained the same; roughly 1.3 billion adults had hypertension, with 82 percent living in low- and middle-income countries (LMICs).

Not all nations have adopted the same criteria for hypertension [18-20]. However, if applied globally, the 2017 ACC/AHA hypertension guidelines would have the following impact in the countries shown below, and the global burden of hypertension would likely rise to at least 1.8 billion individuals.

●In Canada, hypertension rates would increase from 32 to 46 percent [21].

●In India, hypertension rates would increase from 29 to 43 percent [22].

●In China, hypertension rates would increase from 25 to 50 percent [23].

●In South Korea, hypertension rates would increase from 28 to 48 percent [24].

CONTROL OF HYPERTENSION — Data on control of hypertension depends upon the definition of hypertension, criteria for treatment, and goal blood pressure as determined by patient risk factors. Adoption and implementation of the 2017 American College of Cardiology/American Heart Association (ACC/AHA) guidelines impacted both eligibility for treatment and criteria for control in the United States [1]. However, the blood pressure treatment threshold and goals of therapy differ in the Australian, Canadian, and European hypertension guidelines. Consequently, the rates of blood pressure control also differ [1,18-20]. UpToDate recommendations on goal blood pressure are presented elsewhere. (See "Overview of hypertension in adults", section on 'Definitions' and "Goal blood pressure in adults with hypertension".)

The rate of adequate blood pressure control varies among countries but is generally lower in low- and middle-income countries (LMICs) and also lower in males as compared with females [17]. As an example, in a pooled analysis including more 200 countries and over 1.3 billion adults with hypertension (using the prior definition), overall blood pressure control rates in 2019 were 23 percent for females and 18 percent for males. Control rates were the highest in high-income western countries (43 percent for females, 37 percent for males) and lowest in sub-Saharan Africa and Oceania (12 to 13 percent for females, 9 percent for males).

In the United States, sequential information from National Health and Nutrition Examination Surveys (NHANES) and other cohorts (using a definition of hypertension of ≥140 mmHg systolic or ≥90 mmHg diastolic) demonstrate improved age-adjusted blood pressure control from 1988 to 2014 but a decline since 2015 [4,5,7,9,11,25-27]. The control rate was 29 percent in 1988, increased to 49 percent in 2007 to 2008, and increased again to 54 percent in 2013 to 2014; in 2015 to 2016, the control rate dipped to 49 percent, then dropped further to 44 percent in 2017 to 2018. The decline in control from 2009 to 2018 is likely due to lower rates of awareness (from 83 to 79 percent), treatment (from 75 to 71 percent) and a decreased proportion of treated patients who attained adequate blood pressure control (from 71 to 65 percent) [4,5,11,27]. Blood pressure control declined among all age and racial/ethnic groups. Rates of control were lower among Black patients and Hispanic patients compared with White patients, among middle-aged as compared with older adults, and among those who did not attend a health care visit within the prior year or who lacked health insurance [11]. The decline in awareness, treatment, treatment effectiveness, and hypertension control from 2015 to 2018 appeared to reflect a decline in the quality of care, as access to care (health care insurance, regular source of care, and at least one health care visit in the previous year) did not change [27].

In 2020, coincident with the coronavirus disease 2019 (COVID-19) pandemic, rates of hypertension control declined among adults in the United States covered by Medicare, Medicaid, and private insurance [28]. Thus, health systems and clinicians have the added challenge of reversing the temporal decline in hypertension control exacerbated by the pandemic.

Adoption of the ACC/AHA guidelines impacts the rates of blood pressure control. Using pooled NHANES data from 2011 to 2014, among United States adults already taking antihypertensive medication, the proportion of those with blood pressures above goal rose from 39 to 53 percent (figure 2) [2]. However, the segment of United States adults for whom antihypertensive medication is recommended only increased by 2 percent (from 34 to 36 percent), since most patients reclassified as above goal require only nonpharmacologic interventions as initial therapy. (See "Goal blood pressure in adults with hypertension".)

Globally, the rates of blood pressure control are variable by country, and the number of those considered to have inadequate blood pressure control would be expected to similarly rise after adoption of the 2017 ACC/AHA guidelines. As examples:

●Among adults aged 45 to 85 years in Switzerland, 31 percent have blood pressure above goal using the older definition, and 40 percent would have blood pressure above goal using <130/80 mmHg to define control [29]. Among those already taking medication for hypertension, 62 percent are controlled to <140/90 mmHg, and this proportion would decrease to 46 percent if the new treatment goals were adopted.

●Among adults aged 45 to 75 years in China, 41 percent of those being treated with medication for hypertension are not at blood pressure goal using the prior definition. This would increase to 76 percent if the new blood pressure guidelines were adopted [30].

Methods to improve control rates — Methods to improve hypertension control rates typically aim to decrease clinician inertia and to increase patient adherence to antihypertensive therapy:

●Address therapeutic inertia – Clinician inertia contributes substantially to poor hypertension control [31-33]. In the 2013 to 2016 NHANES cohort, for example, 40 percent of individuals with uncontrolled blood pressure were prescribed only one antihypertensive medication [32]. Another large study examined rates of antihypertensive initiation (or antihypertensive intensification) in older adults in the United States who had an ambulatory care visit in which their blood pressure was above goal (according to the ACC/AHA guidelines) [34]. In 2018, appropriate initiation of antihypertensive medication among untreated individuals occurred in less than 20 percent of visits; appropriate addition of another antihypertensive agent among those already treated occurred in less than 10 percent of visits. This represented a decrease in prescribing compared with data from 2008.

●Address nonadherence – Nonadherence to antihypertensive therapy is also common; partial or complete nonadherence occurs in approximately one-third of hypertension patients. (See "Patient adherence and the treatment of hypertension", section on 'Epidemiology of nonadherence'.)

Various approaches to improve blood pressure control have been studied, including implementation of quality improvement programs (eg, techniques to improve patient follow-up, increase medication adherence, and decrease clinician inertia) [35-37]. As examples:

●Control rates as high as 80 percent were achieved in a large-scale group practice that implemented a five-component quality improvement program, which included [38]:

•Formation of a registry to identify and track hypertensive patients

•Treatment algorithms including initial single-pill combinations

•Prompt follow-up of patients with uncontrolled hypertension with medical assistants for blood pressure checks

•Promotion of single-pill combination therapy

•Regular feedback about hypertension control performance provided to local practices and medical directors

In this same population, additional efforts (such as providing clinicians with feedback about their performance in Black patients, White patients, and other historically underserved groups; integrating culturally tailored communications skills; playing videos in waiting rooms that featured the stories of Black patients with hypertension; and introducing large group appointments) further improved blood pressure control rates and narrowed the racial disparity in hypertension control between Black patients and White patients [39].

●Similar control rates were observed in a study that implemented a multicomponent intervention consisting of home visits by health workers, clinician education, and weekly text messages to patients [40].

In addition, programs utilizing financial incentives to clinicians (pay for performance) may be successful in increasing rates of blood pressure control [41-43]. As examples:

●In New York City, 84 small (fewer than 10 clinicians) primary care practices implementing an electronic health record were randomly assigned to receive or not receive financial incentives to achieve certain benchmarks, including adequate blood pressure control among their hypertensive patients [42]. Incentives were larger for patients with additional comorbidities and for those who had Medicaid insurance. After approximately nine months, financial incentives significantly increased blood pressure control rates as compared with no incentive (by 9.7 versus 4.3 percent among those without other comorbidities; by 9.5 versus 1.7 percent among those with diabetes or preexisting vascular disease).

●In a similar study, the effect of financial incentives to achieve blood pressure control was analyzed in 12 Veterans Affairs outpatient clinics [43]. Financial incentives provided to individual clinicians, but not to whole practices, significantly increased control rates as compared with control (by 8.8 versus 0.5 percent).

Using estimates of the effects of various interventions, the hypothetical impact that improving adherence, shortening follow-up intervals, and reducing clinician inertia would have on population blood pressure control was predicted (table 1) [44]:

●If adherence to antihypertensive medication increased from 57 to 100 percent, population hypertension control would improve by 11 percent.

●If follow-up after alterations in antihypertensive therapy was 1 week rather than 14 weeks, population hypertension control would improve by 22.

●If a new class of antihypertensive medication was prescribed for patients with uncontrolled blood pressure during 62 percent of clinician visits rather than 12 percent of visits, population hypertension control would improve by 33 percent.

Although achieving each of these process goals is realistically unlikely, improvements in all three measures, particularly therapeutic intensification, would significantly improve rates of hypertension control.

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Hypertension in adults".)

SUMMARY

●Prevalence of hypertension – The prevalence of hypertension depends upon the definition of hypertension. In 2017, the American College of Cardiology/American Heart Association (ACC/AHA) lowered the threshold for the definition of hypertension; these guidelines have not been adopted globally.

The ACC/AHA definition of hypertension (ie, taking antihypertensive medication or having a systolic pressure ≥130 mmHg and/or a diastolic pressure ≥80 mmHg) has increased the prevalence substantially. In the United States, the prevalence of hypertension in adults under this definition is approximately 45 percent (compared with approximately 30 percent using the previous definition of ≥140 mmHg systolic or ≥90 mmHg diastolic) (figure 1). Global prevalence rates are similar to those in the United States. (See 'Prevalence of hypertension' above.)

●Rates of hypertension control – The proportion of United States adults already on antihypertensive medication who have adequate blood pressure control (defined as a blood pressure <140/<90 mmHg) decreased from 71 to 65 percent from 2013 to 2018. Globally, the rates of blood pressure control are variable by country, and the number of those considered to have inadequately controlled blood pressure would be expected to rise if 2017 ACC/AHA guidelines were adopted. (See 'Control of hypertension' above.)

●Methods to improve hypertension control – Improved rates of blood pressure control lead to decreased cardiovascular morbidity. Methods to improve rates of control, including hypertension treatment algorithms, patient registries, combination therapy single-pill treatment, more frequent follow-up (including non-clinician visits) for patients with uncontrolled hypertension (table 1), and financial incentives for medical providers, have been used with success. (See 'Methods to improve control rates' above.)

ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Norman Kaplan, MD, who contributed to earlier versions of this topic review.