[Effet blouse blanche résiduel : un outil pertinent en soins premiers?]

Abstract

Background: White coat effect (WCE) and white coat hypertension (WCH) are hardly both compared in primary care.

Objective: To assess the usefulness of repeated measures of systolic blood pressure (SBP) to dissociate various forms of white-coat interactions.

Methods: An open cross-sectional study on consecutive patients treated or not for high blood pressure was made in family physicians' offices. SBP was measured 5 times by an electronic device. Measurements were performed before (SBP1) and after (SBP5) the office visit by a lay assistant and at the beginning (SBP2), middle (SBP3) and end (SBP4) of visit, by the family physician. Home BP (HBPM) was measured from 3 consecutive days by the patient. WCE and office WCE tail (OWCET) were defined, respectively, as a 10 mmHg SBP increase or decrease between SBP2-SBP1 or SBP4-SBP2. WCH was considered when HBPM was normal (SBP < 135 mmHg) at home and high during the SBP2 office visit.

Results: Two hundred five patients (134 women versus 71 men, ratio 1.9, aged 59.8±15.7 years) were recruited. In categorical terms, there were 51 patients (25%) who presented with WCE, OWCET was seen in 121 patients (62%) and 47 patients (23%) had WCH. Only 36 patients (18%) presented both OWCET and WCE and 32 (16%) had both OWCET and WCH. The receiver operating characteristic curves (ROCs) of OWCET in diagnosing WCE or WCH were respectively 0.67 (p<0.0001) and 0.53 (NS).

Conclusion: Thus, OWCET was predictive of WCE and not of WCH and it is worthwhile to be measured in the family physician office.

Keywords: Automesures tensionnelles; Blood pressure measurement; Effet blouse blanche; Home blood pressure; Mesure de pression artérielle; White-coat effect.