Classifications of High Blood Pressure (Hypertension)
According to the 2017 ACC/AHA guidelines, blood pressure is categorized into four levels: normal, elevated, stage 1 hypertension, and stage 2 hypertension, with specific systolic and diastolic blood pressure thresholds for each category. 1
Blood Pressure Categories
The current classification of blood pressure in adults according to the 2017 ACC/AHA guidelines is as follows:
| BP Category | Systolic BP | Diastolic BP |
|---|---|---|
| Normal | <120 mm Hg | and <80 mm Hg |
| Elevated | 120-129 mm Hg | and <80 mm Hg |
| Hypertension Stage 1 | 130-139 mm Hg | or 80-89 mm Hg |
| Hypertension Stage 2 | ≥140 mm Hg | or ≥90 mm Hg |
Note: Individuals with SBP and DBP in two different categories should be designated to the higher BP category. 1
Key Points About Blood Pressure Classification
Measurement Requirements: Blood pressure classification should be based on an average of ≥2 careful readings obtained on ≥2 occasions, as detailed in clinical practice guidelines 1
Revised Definition: This categorization differs from previous JNC 7 guidelines, with stage 1 hypertension now defined at lower thresholds (130-139/80-89 mm Hg) than before 1
Cardiovascular Risk: The classification is based on observational data showing a gradient of progressively higher cardiovascular disease (CVD) risk from normal BP to elevated BP and stage 1 hypertension 1
- Hazard ratios for coronary heart disease and stroke were between 1.1-1.5 for BP of 120-129/80-84 mm Hg versus <120/80 mm Hg
- Hazard ratios increased to 1.5-2.0 for BP of 130-139/85-89 mm Hg versus <120/80 mm Hg 1
Clinical Implications
Elevated BP: Individuals with elevated BP (120-129/<80 mm Hg) should receive lifestyle modification recommendations to prevent progression to hypertension 1
Stage 1 Hypertension: Those with stage 1 hypertension (130-139/80-89 mm Hg) may require pharmacological therapy based on their overall cardiovascular risk assessment 1, 2
Stage 2 Hypertension: Patients with stage 2 hypertension (≥140/≥90 mm Hg) typically require both lifestyle modifications and antihypertensive medication 1, 2
Hypertensive Crisis
Although not part of the standard classification, hypertensive crisis is an important clinical entity:
Hypertensive Urgency: Severe hypertension (typically >180/120 mm Hg) with minimal or no end-organ damage 3
Hypertensive Emergency: Severe hypertension with acute end-organ damage (cardiac, renal, neurological) requiring immediate treatment 3
Lifetime Risk and Implications
The lifetime risk of developing hypertension is substantial:
- By age 65, approximately 37% of individuals develop hypertension 1
- For adults aged 45 and older, the 40-year risk ranges from 84% to 93% depending on ethnicity, with higher rates among African Americans and Hispanics 1
Important Considerations in Classification
- When SBP and DBP fall into different categories, the higher category should be used for classification 1
- Multiple BP measurements improve classification accuracy, especially for initial readings above normal 4
- The classification system is most valuable for untreated adults to guide prevention or treatment decisions, but also useful for assessing treatment success 1
This classification system provides a framework for clinical decision-making regarding prevention and treatment strategies to reduce cardiovascular morbidity and mortality associated with hypertension.