title: A novel approach to office blood pressure measurement: 30-minute office blood pressure vs daytime ambulatory blood pressure.
abstract: OBJECTIVE
  Current office blood pressure measurement (OBPM) is often not executed according to guidelines and cannot prevent the white-coat effect. Serial, automated, oscillometric OBPM has the potential to overcome both these problems. We therefore developed a 30-minute OBPM method that we compared with daytime ambulatory blood pressure.
  
  
  METHODS
  Patients referred to a primary care diagnostic center for 24-hour ambulatory blood pressure monitoring (ABPM) had their blood pressure measured using the same validated ABPM device for both ABPM and 30-minute OBPMs. During 30-minute OBPM, blood pressure was measured automatically every 5 minutes with the patient sitting alone in a quiet room. The mean 30-minute OBPM (based on t = 5 to t = 30 minutes) was compared with mean daytime ABPM using paired t tests and the approach described by Bland and Altman on method comparison.
  
  
  RESULTS
  We analyzed data from 84 patients (mean age 57 years; 61% female). Systolic and diastolic blood pressures differed from 0 to 2 mm Hg (95% confidence interval, -2 to 2 mm Hg and from 0 to 3 mm Hg) between mean 30-minute OBPM and daytime ABPM, respectively. The limits of agreement were between -19 and 19 mm Hg for systolic and -10 and 13 mm Hg for diastolic blood pressures. Both 30-minute OBPM and daytime ABPM classified normotension, white-coat hypertension, masked hypertension, and sustained hypertension equally.
  
  
  CONCLUSIONS
  The 30-minute OBPM appears to agree well with daytime ABPM and has the potential to detect white-coat and masked hypertension. This finding makes 30-minute OBPM a promising new method to determine blood pressure during diagnosis and follow-up of patients with elevated blood pressures.
authors.affiliation: Department of Primary and Community Care, Radboud University Nijmegen Medical Centre, The Netherlands. m.vanderwel@elg.umcn.nl
authors.forename: Mark C
authors.initials: MC
authors.lastname: van der Wel
authors.forename: Iris E
authors.initials: IE
authors.lastname: Buunk
authors.forename: Chris
authors.initials: C
authors.lastname: van Weel
authors.forename: Theo A B M
authors.initials: TA
authors.lastname: Thien
authors.forename: J Carel
authors.initials: JC
authors.lastname: Bakx
mesh_terms: D000465:Algorithms; D001794:Blood Pressure; D018660:Blood Pressure Monitoring, Ambulatory / Q000295:instrumentation / Q000379:methods*; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D006973:Hypertension / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D013223:Statistics as Topic; D013997:Time Factors