White coat hypertension in a general practice. Prevalence, cardiovascular risk factors and clinical implications

[Variations in the prevalence and patient profile of white-coat syndrome, according to its definition using self-measurement of blood pressure at home]

OBJECTIVE

To calculate the prevalence of white-coat syndrome (WCS) in patients with hypertension, comparing the two most common definitions and their effect on the profile of the patient with WCS.

DESIGN

Cross-sectional, descriptive study.Setting. Urban health centre.Patients. Hypertense patients selected by simple randomised sampling from among those included in the hypertension programme.

MEASUREMENTS

Clinical blood pressure (CBP) from the previous year was collected. Home blood pressure (HBP) was measured by the patient with an electronic sphygmomanometer. Age, sex, further tests (analysis and electrocardiogram) and other clinical features were also recorded. WCS was defined as when CBP was above/equal to 140/90 mmHg and HBP was under 135/85 mmHg or when the difference between CBP and HBP was more than/equal to 20 mmHg systolic and/or 10 mmHg diastolic pressure.

RESULTS

In 154 hypertense patients (60.4% women) between 38 and 92 years old, mean CBP (141.1/85.3) was higher than mean HBP (136.8/79.8). WCS prevalence varied (p = 0.001), depending on the definition used (20.1% and 36.4%). The systolic and diastolic mean CBP of the last year were higher in those patients with WCS (p < 0.001 for diastolic pressure). The profile of hypertense patients with WCS varied according to the definition used.

CONCLUSIONS

WCS is common in hypertense patients treated in Primary Care and may condition an inadequate assessment of the degree of blood pressure monitoring. As the way of defining WCS conditions its prevalence, its profile and clinical decision-taking, it is essential to agree a uniform definition for practical use.