Doctors usually take a blood pressure reading in only one arm, but a new study in Hypertension suggests they should be checking both. The difference between the two readings may be a marker of increased risk for cardiovascular disease — and death.
Researchers combined data in 24 previous studies that measured bilateral blood pressure in 53,827 men and women over 18. The studies included only people examined in general health clinics, eliminating any who were seen in specialty heart settings.
In total, there were 4,939 deaths from any cause, including 1,435 deaths related to cardiovascular disease, and 5,800 fatal and nonfatal cardiovascular events, including heart attacks, episodes of angina or strokes. After adjusting for age, sex, smoking, and diagnoses of diabetes and hypertension, they found that for each 5 millimeter increase in the difference between left and right arm systolic readings (the top number), there was a 5 percent increase in the risk for death from any cause, a 6 percent increase in cardiovascular death and a 9 percent increase in the risk for a first cardiovascular event.
“This large study gives some precision to the numbers,” said the lead author, Christopher E. Clark, a senior clinical lecturer at the University of Exeter Medical School in England. “A 10 millimeter difference between arms means a 10 percent increase in risk, and that’s substantial enough to reclassify people into groups to be treated more aggressively.”