Does home blood pressure allow for a better assessment of the white-coat effect than ambulatory blood pressure?

Background: The difference between clinic and ambulatory blood pressure (BP) is a poor estimate of the true white-coat effect (WCE) measured with beat-to-beat recording. Method: We investigated whether the difference between clinic and home BP (home WCE) was a better estimate of true WCE than ambulatory WCE. In 73 young hypertensives, ambulatory WCE was calculated as the difference between clinic BP and the mean of two 24-h BP recordings, and home WCE as the difference between clinic and home BP (HBP) measured over 6 months. All individuals underwent beat-to-beat BP monitoring with the Finometer. During the recording, a white-coat test (true WCE) and a public speaking test were performed. Results: Ambulatory WCE correlated with home WCE (P < 0.001 for systolic and diastolic BPs). However, both surrogate WCEs were unrelated to true WCE (P=0.93/0.36 and P=0.11/0.36, respectively). True WCE correlated with the BP reaction to public speaking (P<0.001/P<0.001), whereas both surrogate WCEs were unrelated to the BP response to this test (all P > 0.21). Individuals were divided into two groups according to whether BP response to the doctor's visit was above (WCH+) or below (WCH-) the median. WCH+ patients had similar clinic and ambulatory BPs to WCH- but showed a higher BP response to public speaking. Conclusion: As previously observed for ambulatory WCE, home WCE does not reflect the true BP reaction to doctor's visit. BP response to psychosocial stressors is increased in individuals with hyperreactivity to doctor's measurement but not in individuals with white-coat hypertension identified with either ambulatory or HBP measurement.