Abstract
PURPOSE 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.
Footnotes
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Conflicts of interest: Carel Bakx and Mark van der Wel collaborate in a research project aiming at improvement of hypertension management (NAMI-study, http://www.clinicaltrials.gov: NCT00457483) with an unconditional grant by Novartis to cover the material costs of the study. As head of the Department of Primary and Community Care, Chris van Weel supervises research projects some of which (in part) are funded as unconditional research grants by Bayer, NovoNordisk, Astra-Zeneca, Boehringer Ingelheim, GlaxoSmithKline, or Novartis. Iris Buunk and Theo Thien report no conflicts of interest.
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Findings from this study were presented at Wonca Europe in Basel, Switzerland, September 16-19, 2009.
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Funding support: This study was funded by the Department of Primary and Community Care, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
- Received for publication May 10, 2010.
- Revision received August 27, 2010.
- Accepted for publication September 13, 2010.
- © Annals of Family Medicine, Inc.