Abstract P338: Age and Gender Differences in Response to Repeat Blood Pressure Measurement after Brief Patient Rest Period

Abstract

Background: Office-based blood pressure (BP) measurement is a snapshot of a patient’s ambulatory BP, and is subject to variations which may influence management. Objective: To assess the effect of age and gender on repeat BP measurement after a brief rest period in an outpatient cardiology clinic. Methods: Patient charts reviewed in University-based cardiology clinic identified 170 encounters which contained BP re-measurement data due to elevated initial BP of > 130/80 mmHg. BP was measured initially by a nurse, with the patient in a sitting position and the arm resting at the level of the heart. If BP was > 130/80 mmHg, it was repeated by physician after resting the patient for 15 minutes. There were 86 males (51%) and 84 females (49%); 113 (66%) elderly patients ≥ 60 years of age and 57 (34%) younger patients < 60 years of age. Results: Among all encounters, after a brief rest period, initial systolic BP (SBP) of 153 ± 27 mmHg decreased to 145 ± 27 mmHg (decrease of 8 mmHg; P = 0.003), and initial diastolic BP (DBP) of 87 ± 16 mmHg decreased to 83 ± 15 mmHg (decrease of 4 mmHg; P = 0.04). SBP decreased by 8 mmHg in both males (from 156 ± 30 to 148 ± 27 mmHg) and females (from 151 ± 23 to 143 ± 14) (NS, males versus females). DBP decreased by 5 mmHg in males (from 91 ± 18 to 86 ± 18 mmHg) and by 2 mmHg in females (from 83 ± 12 to 81 ± 12 mmHg) (P = 0.04, males versus females). SBP decreased by 11 mmHg in elderly (from 154 ± 23 to 143 ± 15 mmHg) and 2 mmHg in the young (from 153 ± 33 to 151 ± 30 mmHg) (P=0.02, old versus young). DBP decreased by 3 mmHg in elderly (from 82 ± 12 to 79 ± 12 mmHg) and 4 mmHg in the young (from 97 ± 18 to 93 ± 17 mmHg) (NS, old versus young). Discussion: Hypertension is a challenging public health problem. JNC 7 guidelines recommend that prior to BP measurement, patient should be seated quietly for at least 5 minutes in a chair, with feet on the floor, and arm supported at heart level. This resulted in a significant decrease in BP in our patients. In this study we show that while males and females decrease their systolic BP to the same extent after a brief rest period, males have a greater drop in their diastolic BP than females. Moreover, after the rest period, patients ≥ 60 years of age drop their systolic BP greater than patients < 60 years of age, while there was no significant difference in the drop of their diastolic BP. Given the high reported prevalence of White-coat hypertension in the elderly, between 15% and 25%, this is a clinically significant observation that reinforces that physicians should remeasure the blood pressure, especially the subset of males and the elderly, in whom a bigger decrement may be detected in blood pressure measurement after a brief rest period.