title: Ambulatory blood pressure monitoring: Is 24 hours necessary?
abstract: BACKGROUND
  The variability of blood pressure (BP) makes any single measurement a poor indicator of a patient's true BP. Multiple studies have confirmed the superiority of ambulatory BP measurements over clinic BP measurements in predicting cardiovascular risk; however, this method presents the problem of patient acceptance as it causes frequent arm discomfort and sleep disturbance. We hypothesized that 6 h of daytime BP measurements would result in slightly higher BP readings, yet reveal similar clinical decision making when compared to 24 h of BP measurements.
  
  
  METHODS
  The source for writing this article was a retrospective analysis of 30 patients who underwent ambulatory BP monitoring. Data obtained included: age, sex, ethnicity, baseline medical problems, medications, laboratory values, reason given for ordering 24-h ambulatory BP measurements, ambulatory BP measurements, and a subsequent decision to change medication.
  
  
  RESULTS
  The average BP of the 24-h measurements was 127/75 mm Hg and the average BP of the 6-h daytime measurements was 131/79 mm Hg (SD 15, p = 0.009). Twenty-six out of 30 patients were at goal or pre-hypertensive. Two out of 30 patients had stage 1 hypertension and 2 out of 30 patients had stage 2 hypertension. Thirteen out of 30 patients had nocturnal dipping. Twelve out of 30 patients had a change in medication, but those changes were not associated with the presence or absence of nocturnal dipping (p = 0.5) or other factors beyond mean BP.
  
  
  CONCLUSIONS
  Although there was a statistically significant, 4 mm Hg systolic difference between 24-h and 6-h average BP readings, there was no evidence that this difference led to changes in clinical management. The presence or absence of nocturnal dipping was not associated with a change in medication. We conclude that 6-h daytime ambulatory BP measurements provide sufficient information to guide clinical decision making without the problems of patient acceptance, arm discomfort, and sleep disturbance associated with 24-h BP measurements.
authors: Internal Medicine and Cardiology Division, University of Rochester Medical Center, Rochester, New York, United States. vorn_wp@wp.pl.
authors: Michael
authors: M
authors: Vornovitsky
authors: Benjamin R
authors: BR
authors: McClintic
authors: G Ronald
authors: GR
authors: Beck
authors: John D
authors: JD
authors: Bisognano
mesh_terms: D000959:Antihypertensive Agents / Q000627:therapeutic use; D001794:Blood Pressure / Q000187:drug effects; D018660:Blood Pressure Monitoring, Ambulatory / Q000379:methods*; D002940:Circadian Rhythm; D003661:Decision Support Techniques; D005260:Female; D006801:Humans; D006973:Hypertension / Q000175:diagnosis* / Q000188:drug therapy / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012189:Retrospective Studies; D013997:Time Factors
chemical_list: D000959:Antihypertensive Agents