Blood pressure differences between arms could be important indicator of increased cardiovascular risk (Reuters/Mark Blinch)

Patients suffering from high blood pressure who have different readings in each arm are at a reduced chance of surviving, a study claims.

The authors of the study, published in the BMJ, claim that national guidelines calling for readings to be taken in both arms are not being sufficiently followed.

Researchers at the Peninsula College of Medicine and Dentistry, University of Exeter, studied 230 patients at a rural GP practice in Devon between 1999 and 2002.

Results of the research showed a nine percent increase in risk of death for every one millimetre of mercury (mmhg) of difference in inter-arm pressure.

"Differences in systolic blood pressure between arms can predict an increased risk of cardiovascular events and all cause mortality over 10 years in people with hypertension," the study concludes.

"The difference could be a valuable indicator of increased cardiovascular risk. Bilateral blood pressure measurements should become a routine part of cardiovascular assessment in primary care."

Dr Dae Hyun Kim, from Harvard Medical School, praised the study, but stressed that more work was needed to establish the link between inter-arm blood pressure readings and mortality.

"Because true within person variations in blood pressure exist and measurement errors occur, repeated simultaneous blood pressure measurements are needed for accurate measurement of differences between arms," he said.