title: Consistency of blood pressure differences between the left and right arms.
abstract: BACKGROUND
  It is unclear to what extent interarm blood pressure (BP) differences are reproducible vs the result of random error. The present study was designed to resolve this issue.
  
  
  METHODS
  We enrolled 147 consecutive patients from a hypertension clinic. Three sets of 3 BP readings were recorded, first using 2 oscillometric devices simultaneously in the 2 arms (set 1); next, 3 readings were taken sequentially for each arm using a standard mercury sphygmomanometer (set 2); finally, the readings as performed for set 1 were repeated (set 3). The protocol was repeated at a second visit for 91 patients.
  
  
  RESULTS
  Large interarm systolic BP differences were consistently seen in 2 patients with obstructive arterial disease. In the remaining patients, the systolic BP and the diastolic BP, respectively, were slightly higher in the right arm than in the left arm by 2 to 3 mm Hg and by 1 mm Hg for all 3 sets (P<.01 for all). For the systolic BP and the diastolic BP, respectively, the numbers of patients who had a mean interarm difference of more than 5 mm Hg were 11 (7.5%) and 4 (2.7%) across all 3 sets of readings. Among patients who repeated the test, none had a consistent interarm BP difference of more than 5 mm Hg across the 2 visits.
  
  
  CONCLUSIONS
  The interarm BP difference was consistent only when obstructive arterial disease was present. Although BP in the right arm tended to be higher than in the left arm, clinically meaningful interarm differences were not reproducible in the absence of obstructive arterial disease and are attributable to random variation.
authors.affiliation: Center for Behavioral Cardiovascular Health, Division of General Medicine, Columbia University Medical College, New York, USA. ke2126@columbia.edu
authors.forename: Kazuo
authors.initials: K
authors.lastname: Eguchi
authors.forename: Mona
authors.initials: M
authors.lastname: Yacoub
authors.forename: Juhee
authors.initials: J
authors.lastname: Jhalani
authors.forename: William
authors.initials: W
authors.lastname: Gerin
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Schwartz
authors.forename: Thomas G
authors.initials: TG
authors.lastname: Pickering
mesh_terms: D001132:Arm / Q000502:physiology*; D001157:Arterial Occlusive Diseases / Q000503:physiopathology; D001794:Blood Pressure / Q000502:physiology*; D001795:Blood Pressure Determination / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D017534:Radial Artery / Q000502:physiology