Home blood pressure: variability, comparison with office readings and proposal for reference values. Groupe de la Mesure, French Society of Hypertension.

PURPOSE

A multicentre study was performed on 390 healthy subjects (210 male, 180 female) to evaluate home blood pressure versus office blood pressure.

METHODS

The patients, aged 20-59 years, not on antihypertensive treatment, were not preselected by blood pressure levels. Blood pressure was measured in the doctor's office, using a mercury manometer at the fifth, sixth and seventh minute of rest, and at home by self-measurement using a validated electronic oscillometric device at the fifth, sixth and seventh minute of rest, in the morning and evening, on three consecutive days.

RESULTS

The analysis of office and home measurements at the fifth, sixth and seventh minute of rest showed a significant decrease in blood pressure, mostly between the fifth and sixth minute. There was no significant variation in home pressure over the three consecutive days of measurement. Blood pressures were significantly higher in the evening than in the morning; the mean differences were 3 mmHg for systolic and 1.5 mmHg for diastolic blood pressure. Compared with office blood pressure measurement, home measurement provided significantly lower systolic and diastolic blood pressure means. Of the subjects, 78% showed a higher systolic and 69.9% a higher diastolic blood pressure with office measurement than with home measurement. Systolic and diastolic blood pressure differences were non-significantly higher for females than for males and did not differ with age.

CONCLUSIONS

The comparison of the office and home measurement distributions allowed us to propose reference values for home blood pressure measurement. These were established by choosing blood pressure at the identical percentile for home measurement as we found for office measurement using the World Health Organization criteria (140/90 and 160/95 mmHg). Using this approach, the upper limit for normotension by home measurement would be 127/83 mmHg and for hypertension 147/86 mmHg. Although this approach has no prognostic value, it could be useful for the interpretation of home blood pressure.