Age and Blood Pressure Measurement: Experience with the TM2420 Ambulatory Blood Pressure Monitor and Elderly People

Abstract

The accuracy of the TM-2420 ambulatory blood pressure monitor was assessed in elderly people. Ninety-four subjects (44 men and 50 women), aged 60-94 with systolic blood pressure (SBP) of 97-208 mmHg and diastolic blood pressure (DBP) of 45-109 mmHg, including 23 with isolated systolic hypertension, were studied in three centres. The monitor was compared simultaneously with pairs of observers using the Hawksley random zero sphygmomanometer. The standard deviation of the difference (SDD) between observers was 4.2 mmHg (SBP), 2.9 mmHg (DBP). The mean difference was 0.49 mmHg (SBP) and 0.27 mmHg (DBP). The SDD between the monitor and the average of the observers' readings was 6.7 mmHg (SBP), 5.5 mmHg (DBP); the mean differences were 4.4 mmHg (SBP) and 4.8 mmHg (DBP). There were no significant differences between the two versions of the monitor used (5 and 7) or between the three pairs of observers. The monitor was equally accurate in isolated systolic hypertension (SDD observers and monitor 6.2 mmHg for SBP, 3.9 mmHg for DBP, mean differences 4.3 mmHg for SBP, 4.5 mmHg for DBP). Twenty-four-hour ambulatory blood pressure monitoring was carried out in 129 subjects aged 60-79; 89% of the monitoring attempted were successful with error rates of < 10%. The mean error rate was 3.8%. The device was well tolerated with only 4.7% of the subjects not completing a monitoring.