Family Practice Advance Access originally published online on August 1, 2007
Family Practice 2007 24(5):420-426; doi:10.1093/fampra/cmm035
The inter-arm blood pressure difference and peripheral vascular disease: cross-sectional study
a Primary Care Research Group, Institute of Health and Social Care Research, Peninsula Medical School, St Luke's Campus, Magdalen Road, Exeter, Devon EX1 2LU
b Peninsula R&D Support Unit, Noy Scott House, Barrack Road, Exeter, Devon EX2 5EQ
c Royal Devon and Exeter Hospital (Wonford), Barrack Road, Exeter, Devon EX2 5DW, UK
Correspondence to Christopher E Clark, Primary Care Research Group, Institute of Health and Social Care Research, Peninsula Medical School, St Luke's Campus, Magdalen Road, Exeter, Devon EX1 2LU, UK; Email: christopher.clark{at}pms.ac.uk
Received 11 October 2006; Accepted 17 June 2007.
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Abstract |
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Background. A blood pressure (BP) difference between the upper limbs is often encountered in primary care. Knowledge of its prevalence and importance in the accurate measurement of BP is poor, representing a source of error. Current hypertension guidelines do not emphasize this.
Objectives. To establish the prevalence of an inter-arm blood pressure difference (IAD) and explore its association with other indicators of peripheral vascular disease (PVD) in a hypertensive primary care population.
Methods. This was a cross-sectional study. Primary care, one rural general practice, was the setting of the study. The methods were controlled simultaneous measurement of brachial BPs, ankle-brachial pressure index (ABPI) and tiptoe stress testing in 94 subjects.
Results. In all, 18 of 94 [19%, 95% confidence interval (CI) 11–27%] subjects had mean systolic inter-arm difference (sIAD) 
10 mmHg and seven of 94 (7%, 95% CI 2–12%) had mean diastolic inter-arm difference (dIAD) 10 mmHg. Nineteen of 91 (20%, 95% CI 12–28%) had a reduced ABPI <0.9. There was negative correlation between systolic (Pearson's correlation coefficient – 0.378; P = 0.01) and diastolic (Pearson's correlation coefficient – 0.225; P = 0.05) magnitudes of IAD with ABPI. On tiptoe testing, 9/90 subjects (10%, 95% CI 4–16%) had a pressure drop 20%.
Conclusions. An IAD and asymptomatic PVD are common in a primary care hypertensive population. Magnitude of the IAD is inversely correlated with ABPI, supporting the hypotheses that IADs are causally linked to PVD, and that IAD is a useful marker for the presence of PVD. Consequently, detection of an IAD should prompt the clinician to screen subjects for other signs of vascular disease and target them for aggressive cardiovascular risk factor modification.
Keywords. Hypertension, inter-arm difference, peripheral vascular disease.
Clark CE, Campbell JL, Powell RJ and Thomson JF. The inter-arm blood pressure difference and peripheral vascular disease: cross-sectional study. Family Practice 2007; 24: 420–426.