What is Hypertension (High Blood Pressure, HBP)?

What is HBP (High Blood Pressure/Hypertension)?

HBP (High Blood Pressure), also called hypertension, is a chronic medical condition defined as systolic blood pressure ≥130 mmHg or diastolic blood pressure ≥80 mmHg, and it is the single most important modifiable risk factor for cardiovascular disease, stroke, heart failure, chronic kidney disease, and dementia worldwide. 1

Clinical Definition and Classification

Blood pressure is categorized into four distinct levels based on office measurements 1:

• Normal BP: Systolic <120 mmHg AND diastolic <80 mmHg 1
• Elevated BP: Systolic 120-129 mmHg AND diastolic <80 mmHg 1
• Stage 1 Hypertension: Systolic 130-139 mmHg OR diastolic 80-89 mmHg 1
• Stage 2 Hypertension: Systolic ≥140 mmHg OR diastolic ≥90 mmHg 1

The traditional definition (≥140/90 mmHg) has been updated because cardiovascular risk increases continuously throughout the blood pressure range, with no apparent threshold value, starting as low as 115/75 mmHg 1.

Why HBP Matters: Impact on Morbidity and Mortality

High blood pressure directly causes life-threatening complications 1:

• Cardiovascular disease: HBP is the leading risk factor for ischemic heart disease and heart failure 1
• Stroke: The most severe consequence of hypertension, with HBP accounting for up to half of total stroke mortality in some populations 2
• Chronic kidney disease: Progressive kidney damage leading to renal insufficiency and failure 1
• Dementia: Contributes to cognitive decline and vascular dementia 1
• Premature death: In 2015,8.5 million deaths globally were attributable to systolic blood pressure >115 mmHg, with 88% occurring in low- and middle-income countries 1

Each 10 mmHg reduction in systolic blood pressure decreases cardiovascular disease events by approximately 20-30% 3.

Global Burden and Epidemiology

The prevalence and distribution of hypertension has shifted dramatically 1:

• Approximately 116 million adults in the US and over 1 billion adults worldwide have hypertension 3
• Prevalence is now higher in low- and middle-income countries than in high-income countries 1
• Blood pressure has declined in high-income regions since the 1970s but has risen in East, South and Southeast Asia, Oceania, and sub-Saharan Africa 1
• Among US adults, approximately 45% currently have high blood pressure 4
• Lifetime risk: Nearly 90% of middle-aged adults (55-65 years) who are not yet hypertensive will develop hypertension over their remaining lifetime 1

What Causes HBP

Hypertension results from complex interactions between environmental, genetic, and pathophysiological factors 5:

Environmental and lifestyle factors 1:

• Long-term caloric intake exceeding energy expenditure (obesity)
• Chronic excessive dietary sodium intake
• Excessive alcohol consumption (>20 drinks per week)
• Physical inactivity
• Psychosocial stressors

Pathophysiological mechanisms 5:

• Multiple organ systems are involved including vascular, renal, and neurohormonal systems
• Genetic predisposition plays a significant role
• Secondary causes must be ruled out, particularly in resistant hypertension 1

The Critical Problem: Poor Control Rates

Despite effective treatments being available, only 44% of US adults with hypertension have their blood pressure controlled to <140/90 mmHg, and control rates to the more stringent <130/80 mmHg target are estimated as low as 30% 3, 4. Control rates peaked at 53.8% in 2013-2014 but declined to 43.7% by 2017-2018 1.

Key Clinical Pitfalls

Common mistakes in HBP management 1:

• Inaccurate blood pressure measurement: Office measurements must be standardized; consider ambulatory or home blood pressure monitoring for confirmation 1
• Failure to assess overall cardiovascular risk: Blood pressure level alone should not determine treatment; consider smoking, diabetes, lipid abnormalities, age, and other risk factors 1
• Undertreatment: Many patients require multiple medications to achieve blood pressure goals, but clinicians often fail to intensify therapy 1
• Missing secondary causes: Particularly primary aldosteronism, which affects approximately 20% of resistant hypertension cases but is screened in only 1.6-2.1% of patients 1

Race and Age Considerations

Black patients are especially sensitive to certain interventions 1:

• Reduced salt intake has greater blood pressure-lowering effects
• Increased potassium intake is particularly effective
• The DASH diet produces enhanced benefits

Older individuals (≥65 years) 1:

• After age 50, systolic blood pressure becomes the dominant predictor of cardiovascular risk
• Diastolic pressure tends to fall after age 50 while systolic continues to rise
• More than half of Americans over age 65 have hypertension
• Older adults can successfully make and sustain dietary changes 1