Objective

To investigate 24-h ambulatory blood pressure measurements (ABPM) as a tool for long-term prediction of future blood pressure (BP) status in high normal and low stage 1 hypertensives.

Design, setting and participants

A total of 165 men from a population screening program with diastolic BP (DBP) 85-94 mmHg and a systolic BP (SBP) < 150 mmHg performed a 24-h ABPM. Ten years later, 120 participants (73%) returned for renewed measurements.

Main outcome measures

Blood pressure status at 10 years.

Results

At the 10-year follow-up, 53% of the participants were classified as hypertensive (HT) (BP > or = 140/90 or taking anti-hypertensive medication) and 47% were classified as normotensive (NT) (BP < 140/90 mmHg). There was no significant baseline differences in office SBP levels between those who were normotensive or hypertensive at follow-up (136/91 versus 138/92 mmHg), whereas both SBP and DBP night-time levels were significantly lower in the future normotensives as compared to the future hypertensives (107/69 versus 112/74 mmHg, P < 0.01). Using recommended normalcy night-time ABP levels of < 120/75 mmHg in addition to office BP (140/90) at baseline, over 85% of the subjects were correctly classified provided they met both clinic and ambulatory night-time criteria for HT and NT classification at baseline.

Conclusion

The use of ABPM in addition to office BP's in patients with borderline hypertension greatly increases the possibility of identifying those individuals who are at a very small risk of developing future hypertension. This could potentially lead to considerable savings in both patient anxiety, physician time and resource consumption.