NICE guidance due in August will advise GPs to use 24-hour ambulatory BP monitors to confirm hypertension. GPs have warned that the plans will increase their workload and that they will need funds to buy the devices.
But US research now shows repeat measurements of BP at home are less likely to lead to misclassified hypertension than single readings at a surgery. Researchers from the Durham Veterans Affairs Medical Centre in North Carolina said this would reduce the effect of 'white coat hypertension', where patients' BP rises in the presence of a clinician.
They analysed the BP readings of 444 elderly men with poorly controlled hypertension, recorded frequently over 18 months. Readings were taken either in-clinic by a nurse or at home by the patient.
They found a single BP reading in-clinic could not give certainty that patients' BP was in control, and was likely to misclassify a patient as hypertensive. The percentage of patients deemed to have controlled systolic BP - under 140mmHg - varied by approach. Readings in clinic were on average 15.5mmHg higher than those taken in controlled conditions by researchers.
The research found individual patients' BP readings varied widely. Repeat measurement could limit this but 'would not eliminate white coat effects and is not practical for most patients and providers'.
The researchers concluded that home monitoring could improve BP testing and cut inappropriate treatment.