Validation of two devices for self-measurement of blood pressure by elderly patients according to the revised British Hypertension Society protocol: the Omron HEM-722C and HEM-735C.

BACKGROUND

The validation of self-measurement devices for clinical use by elderly patients has been recommended. The Omron HEM-722C device has recently been validated according to the British Hypertension Society (BHS) protocol for use for general populations and the Omron HEM-735C is a new fully automatic device with a high capacity for storage of measurements that is integrated with a personal computer.

OBJECTIVE

To perform a clinical validation for use by elderly people of the Omron HEM-722C and HEM-735C devices according to the revised protocol of the BHS and the criteria of the Association for the Advancement of Medical Instrumentation (AAMI).

METHODS

We carried out a main validation test according to the revised BHS protocol for validation procedures for special groups on two groups of 30 subjects aged more than 65 years (29 men and 31 women), 11 of 30 with systolic blood pressures (SBP) <110mmHg, 10 of 30 with SBP >200 mmHg, 15 of 30 with diastolic blood pressures (DBP( <70 mmHg and 10 of 30 with DBP >110 mmHg. The results were graded according to the BHS system from A to D.

RESULTS

The Omron HEM 722C achieved an overall A/A grading and satisfied the AAMI criteria for accuracy whereas the Omron HEM-735C achieved an overall B/A grading and satisfied the AAMI criteria for accuracy. The sphygmomanometer measurements were 147 +/- 31/79 +/- 15 and 144 +/- 30/78 +/- 15 mmHg (means+/-SD) respectively, for the models 722C and 735C. The average differences between mercury sphygmomanometer and HEM-722C readings for SBP and DBP were, respectively, 0.76+/-5 and 0.41+/-8 mmHg; those for HEM-735C were, respectively, 0.24+/-8 and 0.9+/-8 mmHg. Readings of the HEM-722C device differed by less than 5 mmHg for 76% of systolic readings and 96% of the readings differed by less than 10 mmHg. Diastolic measurements differed by less than 5 mmHg for 71% and less than 10 mmHg for 71 and 87% of all readings. Readings of the HEM-735C device differed by less than 5 mmHg for 68% of systolic readings and 74% of the readings differed by less than 10 mmHg. Diastolic measurements differed by less than 5 mmHg in 74% and less than 10 mmHg in 88 and 87% of all readings.

CONCLUSIONS

On the basis of these results, for elderly subjects both self-measurement devices (Omron HEM-722C and HEM-735C) satisfied the validation criteria of the BHS and therefore can be recommended for the clinical measurement of blood pressure in elderly patients.