We agree with Adjei-Gyamfi et al that the reliability of home blood pressure monitoring is crucial to its success. This requires attention to both the sphygmomanometer and the measuring technique. Given around 5% of patients will have a 10 mmHg or more difference between their arms, then an initial check for inter-arm difference is important. However, assessing inter-arm differences reliability requires simultaneous blood pressure measurement, and so this will need to be done in their GP's office rather than at home. At home the patient should then use the arm with the higher blood pressure. Clark and Campbell's suggestion that a single simultaneous pair of measurements may be sufficient to rule out high inter-arm differences appears an important step in making this check practical. However, as they suggest, both the technique and the implications are in need of further research and future blood pressure studies should incorporate dual arm measurement as part of the protocol.
- © British Journal of General Practice, 2009.