Comparison of home and clinical blood pressure measurements: clinical applications

While measurement of blood pressure in the doctor's office remains the method of reference of the WHO, self-measurement yields complementary information, namely: measures outside the surgery, good estimation of the level of blood pressure at home from several day's data, better reproducibility related to standardized conditions of measurement imposed by the constraints of immobility and manoeuvre of the machine. The modalities of variation of BP by automeasure are known: diminution in the BP by automeasure of about 2 to 4 mm Hg between the first and the third measure performed at 1-min intervals, no significant evolution over 3 days and BP more elevated in the evening than in the morning. In comparison with the WHO data, the BP is significantly lower. Recently reference values have been proposed, giving as the upper threshold of normotension = 127/ 83 mm Hg and hypertension = 147/ 86 mm Hg. As regards diagnosis SM allows the identification of "white coat hypertension", and thus avoids treating these patients. The indirect prognostic value via target organ effect is under evaluation, and may be at the same level as ambulatory blood pressure measurement (ABPM). Given the utilisation of validated automatic machines and a rigorous methodology SM is beginning to be used satisfactorily in clinical trials. Numerous studies are still necessary in order to clearly define the place of SM in comparison to WHO and AMBP in the management of hypertension.