title: Inter-arm blood pressure difference in type 2 diabetes: a barrier to effective management?
abstract: BACKGROUND
  Previous studies have identified a substantial prevalence of a blood pressure difference between arms in various populations, but not patients with type 2 diabetes. Recognition of such a difference would be important as a potential cause of underestimation of blood pressure.
  
  
  OBJECTIVE
  To measure prevalence of an inter-arm blood pressure difference in patients with type 2 diabetes, and to estimate how frequently blood pressure measurements could be erroneously underestimated if an inter-arm difference is unrecognised.
  
  
  METHODS
  Cross-sectional study.
  
  
  METHODS
  Five surgeries covered by three general practices, Devon, England.
  
  
  METHODS
  Patients with type 2 diabetes underwent bilateral simultaneous blood pressure measurements using a validated protocol. Mean blood pressures were calculated for each arm to derive mean systolic and diastolic differences, and to estimate point prevalence of predefined magnitudes of difference.
  
  
  RESULTS
  A total of 101 participants were recruited. Mean age was 66 years (standard deviation [SD] = 13.9 years); 59% were male, and mean blood pressure was 138/79 mmHg (SD = 15/10 mmHg). Ten participants (10%; 95% confidence interval [CI] = 4 to 16) had a systolic inter-arm difference > or =10 mmHg; 29 (29%; 95% CI = 20 to 38) had a diastolic difference >/=5 mmHg; and three (3%; 95% CI = 0 to 6) a diastolic difference > or =10 mmHg. No confounding variable was observed to account for the magnitude of an inter-arm difference.
  
  
  CONCLUSIONS
  A systolic inter-arm difference > or =10 mmHg was observed in 10% of patients with diabetes. Failure to recognise this would misclassify half of these as normotensive rather than hypertensive using the lower-reading arm. New patients with type 2 diabetes should be screened for an inter-arm blood pressure difference.
authors.affiliation: Institute of Health Service Research, Peninsula College of Medicine and Dentistry, Exeter, Devon. christopher.clark@pms.ac.uk
authors.forename: Christopher E
authors.initials: CE
authors.lastname: Clark
authors.forename: Colin J
authors.initials: CJ
authors.lastname: Greaves
authors.forename: Philip H
authors.initials: PH
authors.lastname: Evans
authors.forename: Andy
authors.initials: A
authors.lastname: Dickens
authors.forename: John L
authors.initials: JL
authors.lastname: Campbell
mesh_terms: D000368:Aged; D001132:Arm; D001794:Blood Pressure / Q000502:physiology*; D001795:Blood Pressure Determination / Q000379:methods* / Q000592:standards; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology*; D003925:Diabetic Angiopathies / Q000503:physiopathology; D005260:Female; D006801:Humans; D006973:Hypertension / Q000503:physiopathology; D008297:Male