I was somewhat surprised that the authors of the otherwise comprehensive articles on hypertension in the October 2012 BCMJ [“Assessing and managing hypertension” 54:390-412] did not take the opportunity to remind us of the existence of inter-arm difference in blood pressure and its significance. The 2012 Canadian Hypertension Education Program (CHEP) recommendations state, “For initial readings, take the blood pressure in both arms and subsequently measure it in the arm with the highest reading.” Failure to follow these recommendations can delay the diagnosis of hypertension.
Inter-arm difference is relatively common. In a study of 230 people receiving treatment for hypertension in primary care, Clark and colleagues found that 24% of people being treated for hypertension had a mean inter-arm difference in systolic blood pressure of 10 mm Hg or more and 9% of 15 mm Hg or more.
Are such differences of clinical significance? Clark and colleagues think so. In their meta-analysis of 20 studies, they found that a difference of 10 mm Hg or more was strongly associated with subclavian stenosis and that a difference of 15 mm Hg or more was associated with peripheral vascular disease.
They conclude that a difference of 10 mm Hg, or of 15 mm Hg or more between arms might help to identify patients who need further vascular assessment.
Unfortunately, pharmacies with blood pressure measuring stations are set up so that it is virtually impossible to use the right arm for measurement.
Even in primary care, bilateral blood pressure measurements are not routine, probably for similar ergonomic reasons.
Although some physicians may be deterred by reading that simultaneous rather than sequential measurements are required, this is not practical—nor is it required by CHEP guidelines.
—Colin Campin, MB
Salt Spring Island
1. Clark CE, Taylor RS, Shore AC, et al. The difference in blood pressure readings between arms and survival: Primary care cohort study. BMJ 2012;344:e1327.
2. Clark CE, Taylor RS, Shore AC, et al. Association of a difference in systolic blood pressure between arms with vascular disease and mortality: A systematic review and meta-analysis. Lancet 2012;379(9819):905-914.
Above is the information needed to cite this article in your paper or presentation. The International Committee
of Medical Journal Editors (ICMJE) recommends the following citation style, which is the now nearly universally
accepted citation style for scientific papers:
Halpern SD, Ubel PA, Caplan AL, Marion DW, Palmer AM, Schiding JK, et al. Solid-organ transplantation in HIV-infected patients. N Engl J Med. 2002;347:284-7.
About the ICMJE and citation styles
The ICMJE is small group of editors of general medical journals who first met informally in Vancouver, British Columbia, in 1978 to establish guidelines for the format of manuscripts submitted to their journals. The group became known as the Vancouver Group. Its requirements for manuscripts, including formats for bibliographic references developed by the U.S. National Library of Medicine (NLM), were first published in 1979. The Vancouver Group expanded and evolved into the International Committee of Medical Journal Editors (ICMJE), which meets annually. The ICMJE created the Recommendations for the Conduct, Reporting, Editing, and Publication of Scholarly Work in Medical Journals to help authors and editors create and distribute accurate, clear, easily accessible reports of biomedical studies.
An alternate version of ICMJE style is to additionally list the month an issue number, but since most journals use continuous pagination, the shorter form provides sufficient information to locate the reference. The NLM now lists all authors.
BCMJ standard citation style is a slight modification of the ICMJE/NLM style, as follows:
- Only the first three authors are listed, followed by "et al."
- There is no period after the journal name.
- Page numbers are not abbreviated.
For more information on the ICMJE Recommendations for the Conduct, Reporting, Editing, and Publication of Scholarly Work in Medical Journals, visit www.icmje.org