[Role of physician-patient dialogue in the "white-coat" effect in arterial hypertension. Reproducibility during the consultation. Existence despite of treatment].

A prospective study in 35 hypertensive patients indicated that blood pressure during a visit was increased by a "white coat" effect in 33 cases out of 35. On average, systolic blood pressure during a visit was 12.4 mmHg (+9%) higher than ambulatory systolic pressure (p < 0.0001), while diastolic pressure was increased by 10.3 mmHg (+11%, p < 0.0001). This alerting reaction is caused above all by dialogue between the physician and patient and lessens during periods of silence. Systolic pressure increased by 13.8 mmHg (+10%, p < 0.0001) during dialogue in comparison with period of silence, and by 18.9 mmHg (+14%, p < 0.0001) in comparison with ambulatory period. Diastolic pressure increased by 8 mmHg (+8%, p < 0.0001) and 14 mmHg (+14%, p < 0.0001) under the same circumstances. This effect would appear to depend upon the emotional content of the dialogue. It could recur to the same extent 30 minutes after the start of the visit. This effect is identical in treated and non-treated hypertensive patients. Thus the persistence of high pressure levels measured during medical visits of treated patients should lead to evaluation of their ambulatory pressure before concluding that treatment is ineffective.