title: Deep breathing: A simple test for white coat effect detection in primary care.
abstract: OBJECTIVE
  White coat hypertension (WCH) is hard to differentiate from sustained hypertension without the use of 24-h ambulatory blood pressure monitoring (ABPM). This invaluable procedure is nevertheless cumbersome and expensive. A simple test of deep breathing over 30 s (DBT) was proposed as a method to unveil WCH.
  
  
  METHODS
  Two hundred and fourteen outpatients referred for the evaluation of uncontrolled hypertension (blood pressure, BP > 140/90 mmHg despite therapy) were enrolled in a controlled clinical trial. The examinees were randomly divided in two groups: control (n = 108; sequential standard BP measurement only) and intervention (n = 106; the same+DBT), using ABPM as the reference standard.
  
  
  RESULTS
  The relative decrease in BP was significantly larger in the intervention group than in the control group, by 15/4 mmHg (p = 0.005). The best detection of WCH was obtained at ≥ 15% systolic BP reduction following DBT, with a positive predictive value of 94.0% (95% CI 72.0-100.0). BP reduction of ≤ 8% may rule WCH out with a negative predictive value of 78.4% (95% CI 64.0 - 85.9).
  
  
  CONCLUSIONS
  DBT is a reliable, inexpensive and fast test for the detection of WCH in primary care.
authors.affiliation: Department of Family Medicine, University of Split, School of Medicine , Split , Croatia.
authors.forename: Marion
authors.initials: M
authors.lastname: Tomičić
authors.forename: Dragomir
authors.initials: D
authors.lastname: Petric
authors.forename: Mirjana
authors.initials: M
authors.lastname: Rumboldt
authors.forename: Vedran
authors.initials: V
authors.lastname: Carević
authors.forename: Zvonko
authors.initials: Z
authors.lastname: Rumboldt
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001794:Blood Pressure; D018660:Blood Pressure Monitoring, Ambulatory; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012119:Respiration; D059466:White Coat Hypertension / Q000175:diagnosis* / Q000503:physiopathology*
keywords: Ambulatory blood pressure monitoring; deep breath test; white coat hypertension