Ambulatory or self blood pressure measurement? Improving the diagnosis of hypertension.

There are major problems with blood pressure (BP) measurement that must be addressed in the diagnosis and treatment of hypertension. Errors in taking BP are widespread and failure to allow for regression to the norm often leads to premature treatment. 'White coat hypertension', a condition in which raised BP levels in the presence of a doctor or nurse do not regress towards the norm on repeated measurement, may be responsible for between 10-20% of our patients being given medication unnecessarily. Ambulatory measurement is becoming an accepted method of attempting to deal with these problems whereas self measurement at home is little used. Used properly, both methods prevent most observer error and bias, eliminate regression to the norm, and allow the diagnosis of 'white coat hypertension'. Both curtail the period necessary to establish patients' 'true' BP. Ambulatory measurement has established scientific advantages but is expensive in time, equipment and staffing. Home measurement at the moment is less reliable but is easier and cheaper. Problems with the accuracy of instruments for home measurement can be solved and, even in their present form, enable the diagnosis of white coat hypertension and help in the diagnosis of many hypertensive patients. Ambulatory monitoring is already undergoing trials in primary care. It is suggested that home measurement should also be more widely used where most patients with hypertension are exclusively managed.