Evaluation of the accuracy and reproducibility of ambulatory blood pressure monitoring in the very elderly using the Takeda TM-2420.

The accuracy and reproducibility of ambulatory blood pressure monitoring (ABPM) were evaluated in the healthy elderly (> or = 75 years) using the Takeda TM-2420 ambulatory BP monitor (A & D Mercury, Australia). Accuracy was assessed from 90 standardised sphygmomanometer and simultaneously recorded TM-2420 BP measurements in 28 subjects with a BP range of 60-210 mmHg. Reproducibility was determined in 19 subjects who underwent four separate days of ABPM by calculating the standard deviation of the mean differences between pairs of recording days (sdd) and the coefficient of reliability (R). Adaptation was also assessed using R. Of 3471 BP measurements in 19 subjects over 76 recording days, 76% were valid readings. The TM-2420 overestimated simultaneously recorded sphygmomanometer measurements with a bias (mean difference, d +/- sdd) of 13.9 +/- 13.9 mmHg for SBP and 7.5 +/- 6.4 mmHg for DBP. The mean sdd between pairs of recording days was greater for SBP (20.0) than for DBP (9.4) but R was very high for both SBP (0.914) and DBP (0.904). Adaptation effects were not detected. ABPM with the TM-2420 is highly reproducible in the elderly. The TM-2420 performs acceptably in 'field' testing and as it overestimates cuff measurements consistently, appropriate adjustment of recorded TM-2420 BP should be possible in elderly individuals.