Objective: To compare clinic and home blood pressures for use in classifying patients in relation to a recent guideline for the diagnosis of hypertension.
Methods: Fifty patients were studied and classified on the basis of clinic pressures, using the Joint National Committee VI criteria, into the categories of normal, high-normal and stage 1, 2 or 3 hypertension. The patients were given instructions for using the Omron IC home-recording device to take their blood pressure daily for 1 week and then return the units for data recall and entry. Average home-recorded pressures were calculated and patients reclassified in terms of the Joint National Committee VI criteria if their home pressures were higher or lower than their clinic pressures.
Results: According to the clinic results, 18% of the participants had normal blood pressure, 16% had high-normal pressure, 48% were hypertensive stage 1, 16% were hypertensive stage 2 and 2% were hypertensive stage 3. Reclassification by recorded home pressures occurred in 54% of the participants: 40% downwards and 14% upwards. Only 46% remained in the same category for both clinic and recorded home pressures.
Conclusion: Recorded home blood pressure measurement provides an accurate, reliable and unbiased assessment. Using the Joint National Committee VI classification system for both clinic and recorded home blood pressures, the data on the home pressures led, in this sample, to a downward classification three times more frequently than an upward one. We therefore conclude that recording home blood pressure is a highly useful method for assigning the appropriate blood pressure classification when using the Joint National Committee VI guidelines.