Ambulatory blood pressure monitoring: non-pharmacological and pharmacological treatment

The main advantages of ambulatory blood pressure monitoring (ABPM) over clinic blood pressure measurements are the following: the lack of an alarm reaction and of observer bias; repeated readings during 24 h in the customary environment of the patient, instead of a single measurement in the doctor's office; superior reproducibility, allowing the sample size of study groups to be reduced substantially; and multiple data, likely to be analysed by several complementary methods. The different non-pharmacological interventions could be classified as follows: probably ineffective (sodium intake restriction, caffeine intake restriction, abstinence from alcohol consumption), probably effective (potassium supplementation, magnesium supplementation, weight reduction by overweight patients, cessation of smoking) and requiring further investigation (psychological interventions, physical activity, dietary lipid level modifications). The effects of pharmacological treatment may be accurately assessed by using ABPM: detailed information is given concerning the duration of action of the antihypertensive drugs; different regimens of the same treatment mayi be compared with each other or with placebo; and the trough: peak ratio can be determined for each drug. It is noteworthy that all of these subtle measurements have to be performed in patients the blood pressure of whom seems to respond adequately to the drug under evaluation. An additional key role for ABPM in clinical trials could be to establish selection criteria both for trial entry and for dose adjustment.