Measurement of blood pressure in primary care.

The value of measuring blood pressure in the clinic is debatable, especially when it is done by doctors. Inherent variability means that true changes in blood pressure can be difficult to detect using clinic readings. Furthermore, misclassification on the basis of clinic readings can occur in people with “normal” underlying blood pressure who are labelled as hypertensive because of the pressor effects of having blood pressure measured in the clinic (white coat hypertension) and those with hypertension who are labelled as normal because clinic readings are lower than the usual blood pressure (masked hypertension). Out of clinic methods of measuring blood pressure, such as ambulatory blood pressure monitoring and home monitoring, are better predictors of cardiovascular outcome than clinic measurements. Self monitoring and self management can lead to better control of blood pressure than monitoring blood pressure in the clinic. However, the evidence base for the treatment of hypertension is based on clinic measurements, and it can be problematic to translate ambulatory and home readings to their clinic equivalent. Therefore, methods to improve the accuracy of the measurement of blood pressure in the clinic remain relevant⇓.