Whether blood pressure
(BP) measured at the wrist
differs from blood pressure
measured at the arm is not well known. The aim of this study was to compare the BP readings obtained at the arm with those obtained at the forearm
and to assess whether the wrist
-arm discrepancies were related to subjects' clinical characteristics.
We measured blood pressure
at the forearm
and at the upper arm
in 85 subjects using conventional sphygmomanometry. Wrist
-arm blood pressure
discrepancies were assessed in relation to gender, age, body mass index, skin-fold thickness, arm size, blood pressure
level, and arterial compliance measured with the HDI/Pulsewave CR-2000.
Results Blood pressure
measured at the wrist
consistently overestimated blood pressure
taken at the arm with a mean (±SD) discrepancy of 8.2±9.7/9.2±6.4 mmHg. The systolic blood pressure
differences were greater in men than in women (p
=0.006) and, among the men, varied according to arm adiposity (positive association, p
=0.01). In men, diastolic blood pressure
differences correlated with diastolic blood pressure
level (negative association, p
=0.01). Among the women, only age (p
=0.04) was a significant positive independent predictor of the wrist
-arm diastolic BP differences.
These results indicate that forearm blood pressure measurement
markedly overestimates upper arm blood pressure
and that the between-site difference may vary from subject to subject. Wrist blood pressure measurement
is not a valid alternative to traditional measurement
at the arm and its use should be discouraged.