Definition of Hypertension
Hypertension is defined as a systolic blood pressure ≥130 mm Hg or a diastolic blood pressure ≥80 mm Hg, based on the current American College of Cardiology/American Heart Association (ACC/AHA) standard adopted by major medical societies. 1
Blood Pressure Categories
The current classification system stratifies blood pressure into distinct categories that guide clinical decision-making:
Normal BP: Systolic <120 mm Hg AND diastolic <80 mm Hg 1
Elevated BP: Systolic 120-129 mm Hg AND diastolic <80 mm Hg 1
Stage 1 Hypertension: Systolic 130-139 mm Hg OR diastolic 80-89 mm Hg 1
Stage 2 Hypertension: Systolic ≥140 mm Hg OR diastolic ≥90 mm Hg 1
Diagnostic Confirmation Requirements
Blood pressure measurements must be confirmed on multiple occasions before diagnosing hypertension to avoid misclassification. 1
Elevated blood pressure readings should be confirmed using measurements on at least two separate occasions 1
Out-of-office blood pressure monitoring (home or ambulatory monitoring) is strongly recommended to confirm the diagnosis and exclude white-coat hypertension 1
Patients with blood pressure ≥180/110 mm Hg and existing cardiovascular disease may be diagnosed at a single visit due to the urgency of intervention 1
Special Population Considerations
Children and Adolescents
The definition differs for pediatric patients based on age-specific percentiles:
Children <13 years: Hypertension is defined as systolic or diastolic BP ≥95th percentile for age, sex, and height 1
Adolescents ≥13 years: The adult definition applies (≥130/80 mm Hg) to align with adult guidelines and simplify transition of care 1
Stage 2 hypertension in children: BP ≥95th percentile + 12 mm Hg, or ≥160/100 mm Hg in adolescents ≥18 years 2
Pregnant Individuals with Diabetes
- Chronic hypertension in pregnancy uses a threshold of 140/90 mm Hg for treatment initiation 1
Evolution of the Definition
The 2017 ACC/AHA guidelines lowered the diagnostic threshold from the previous JNC7 definition of ≥140/90 mm Hg, which has generated significant controversy. 1
This change was primarily driven by:
The continuous dose-response relationship between blood pressure levels and adverse cardiovascular outcomes, with excess risk beginning above 120 mm Hg systolic 1
Results from the SPRINT trial demonstrating benefits of lower blood pressure targets 1
The goal of earlier identification and intervention to prevent cardiovascular morbidity and mortality 3
Clinical Impact of the Revised Definition
The lowered threshold substantially increased hypertension prevalence:
Approximately 31 million additional U.S. adults are now classified as having hypertension under the ACC/AHA definition 1
Overall U.S. prevalence increased from 32% (using ≥140/90 mm Hg) to 46% (using ≥130/80 mm Hg) 1
The largest prevalence increase occurred in adults aged 20-44 years, where male prevalence increased from 11% to 30% 1
Important Caveats
The International Society of Hypertension has expressed concern about global applicability of the lower threshold, particularly in low- and middle-income countries where blood pressure control rates to even 140/90 mm Hg remain below 15%. 1
The pragmatic definition of hypertension should be "that level of BP above which investigation and management does more good than harm" 1
While the continuous relationship between blood pressure and cardiovascular risk is well-established, the optimal threshold for defining hypertension in resource-limited settings remains debated 1
Proper blood pressure measurement technique is critical—measurements must be performed in the seated position, with feet on floor, arm supported at heart level, after 5 minutes of rest, using appropriate cuff size 1