In clinical trials there are numerous well documented phenomena that must be considered during the assay development phase. One particular phenomenon that needs to be considered, particularly in trials that require blood pressure data to be recorded it the white coat hypertension effect.
This essentially an effect that occurs when patients or trial volunteers give unreliable blood pressure readings due to their reaction to being in the unfamiliar setting of a clinic or hospital. The presence of nurses and doctors in their “white coats” can cause some people to become anxious due to various expectations about medical staff and the medical environment and this in turn produces an increase in blood pressure.
Failing to control for this effect can result in data being swayed and ultimately being unreliable. The cost of clinical trials and the organisation involved in them means the consequences of this could have significant consequences. It is clearly important that this effect is controlled for.
There are many different ways in which the white coat hypertension effect may be controlled for in clinical tests and trials. One of the most effective methods is to use ambulatory blood pressure monitors.
By taking blood pressure readings at regular intervals throughout the day the patient or volunteer can acclimatise to the environment they are in and allow their blood pressure to normalise. Where it is not practical to have the volunteer in the clinic or hospital for a twenty four hour period they can be taught how to take their own blood pressure readings from home.
While these methods may control for the effects that medical staff may have on the patient or volunteer they still require that the patient be relatively still while the reading is being taken. This may not reflect the normal circumstances of their life. If a drug is to be tested as to its effects on ordinary life this may not be adequate.
Where a more detailed and representative reading is required the patient may be fitted with a continuous blood pressure monitoring devices. This form of ambulatory blood pressure monitoring can record the volunteers blood pressure throughout the day.