Prehypertension and high normal blood pressure – a fundamental shift in the management of cardiovascular risk?
Hypertension (high blood pressure) is a major risk factor for cardiovascular disease. Recent clinical guidelines have recommended a fundamental shift in the management of cardiovascular risk by recognising and treating ‘prehypertension’ - blood pressure levels which were previously considered to be safe. Dr James Oliver and Prof David Webb review the implications of the new guidelines.
- High blood pressure (hypertension) is a leading cause of disease worldwide.
- Recent US and European clinical guidelines differ in only minor respects.
- Blood pressure (BP) is measured in mm mercury (Hg) as a higher pressure during ejection of blood from the heart (systolic) and as a lower pressure while the heart relaxes and refills with blood (diastolic).
- Normal or optimal BP is less than 120/80.
- Hypertension is a BP above 140/90, and its severity is related to the degree to which it is above this level. Drug treatment is often needed.
- BPs between these levels are now regarded as ‘high normal’ in Europe or ‘prehypertension’ in the US.
- Life-style measures can reduce BP and may prove useful in those with high normal/prehypertension BPs.
- BP control in hypertension is generally poor and requires improvement.
Declaration of interests: No conflict of interests declared
Hypertension is a leading cause of the global disease burden, behind only malnutrition and unsafe sex. Although relatively more important in developed regions, it is also a major and growing cause of disease in the developing world.1
Two major guidelines for the assessment and treatment of hypertension have been published this year, from the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure in the USA (JNC 7),2 and the European Societies of Hypertension and Cardiology.3 While the recommendations in the two guidelines are similar in many respects, there are some differences. For example, the European guideline, but not JNC 7, emphasises the importance of overall cardiovascular risk assessment, rather than a strict focus on hypertension, when making treatment decisions.
The two guidelines classify blood pressure (BP) differently (Figure 1).
Perhaps the most controversial aspect of JNC 7 is that BP in the range 120-139/80-89 mmHg should be diagnosed as ‘prehypertension’. No longer will doctors be able to consider a BP of 120/80 mmHg either normal or completely safe! This is largely based on data from the Framingham Heart Study showing that, within four years, hypertension will develop in 39% of 35-64 year olds and 53% of 65-94 year olds if baseline BP is 130-139/85-89 mmHg, and 18% of 35-64 year olds and 29% of 65-94 year olds i