Evaluation of the overall system precision of the Welch-Allyn transtelephonic home blood pressure monitor in adults with Parkinson's disease

Background Non-invasive blood pressure (BP) devices should be independently evaluated before being used in special populations. The objective of this study was to assess the accuracy of the Welch-Allyn transtelephonic home blood pressure monitor in adults with Parkinson's disease to evaluate the device for use in a large clinical trial involving the safety and efficacy of a monoamine oxidase inhibitor. Methods BP measurements taken with the device were compared with the results obtained by two experienced observers using a mercury sphygmomanometer in patients with Parkinson's disease. The limits of agreement were then calculated for the device and compared with the results of the two observers. Results The agreement parameters between the two observers were -0.5 +/- 2.6 mmHg for systolic BP and 0.1 +/- 2.2 mmHg for diastolic BP. The agreement between the Welch-Allyn transtelephonic device and the observers was -2.6 +/- 4.5 mmHg and -1.9 +/- 3.2 mmHg for systolic and diastolic BP respectively. Nearly 90% of the readings were within 10 mmHg of the observers for both systolic and diastolic BP. Mild tremor had a moderate effect on the validity of the device. Conclusions The Welch-Allyn transtelephonic device demonstrated acceptable precision in this cohort of patients with Parkinson's disease and is considered valid for use in a clinical trial involving these patients. (C) 2002 Lippincott Williams Wilkins.