Overestimation of blood pressure in the elderly.

The blood pressure (BP) of 24 elderly (mean age +/- SD 73 +/- 5 years) and 10 young (35 +/- 11 years) hypertensive patients was measured indirectly by the cuff-mercury sphygmomanometer and directly by intra-arterial recording. The differences between indirect and direct BP (delta BP) recordings were significant (P less than 0.05) for both systolic BP (delta SBP +/- SD 16.55 +/- 15.91 mm Hg) and diastolic BP (delta DBP, 6.97 +/- 9.38 mm Hg) in the elderly group but not in the young group (delta SBP, +/- 2.50 +/- 9.70 mm Hg, delta DBP, +/- -0.03 +/- 6.55 mm Hg). The use of the cuff-mercury method may overestimate systolic and diastolic BP in elderly hypertensive patients.