ACCURACY OF OFFICE BLOOD PRESSURE MEASUREMENT UNDER IDEAL AND NON-IDEAL MEASUREMENT CONDITIONS: A RANDOMIZED CLINICAL TRIAL

Objective: Assessing the impact of suboptimal measurement conditions on the accuracy of office blood pressure (BP) measurement using auscultatory and oscillometric techniques. Design and method: A randomized equivalence clinical trial conducted with 282 adults. The trial arms comprised three deviations from the protocol representing non-ideal blood pressure (BP) measurement conditions: noisy environment, use of a standard adult-sized cuff not indicated for the patient, and a combination of both. Control systolic blood pressure (SBP) and diastolic blood pressure (DBP) measurements were obtained using the auscultatory method, strictly adhering to a standardized measurement protocol. SBP and DBP measurements were obtained by introducing protocol deviations during measurements performed using the auscultatory method, with an aneroid sphygmomanometer, or the oscillometric method, with an clinically validated automated monitor. Auscultatory measurements were performed simultaneously by two observers and verified by a third. For each participant, six sequential measurements were obtained, alternating between the aneroid and automatic monitor, with the first two conducted under ideal conditions and the subsequent ones under non-ideal conditions. Mean difference tests and Bland-Altman plots were employed to evaluate equivalence between methods. Results: Protocol deviations had a greater impact on auscultatory method compared to oscillometric method and on DBP compared to SBP. On average, errors in auscultatory measurements alter SBP by 0.57 mmHg and DBP by 3.29 mmHg. In oscillometric measurements, SBP is altered by 0.20 mmHg and DBP by -0.92 mmHg. The use of a standard adult-sized cuff resulted in greater reductions in accuracy for both methods compared to a noisy environment. The automatic monitor met the equivalence assumptions under both ideal and non-ideal conditions, demonstrating accuracy comparable to that of the manual sphygmomanometer when the BP measurement protocol was strictly followed, as well as in scenarios involving cuff size deviations and noise. In the presence of protocol deviations, the accuracy of the auscultatory method for classifying BP values was 75.18%, while that of the oscillometric method was 74.82%. Conclusions: Oscillometric automatic monitors and sphygmomanometers exhibit equivalent accuracy under both ideal and non-ideal measurement conditions. Under all test conditions, the oscillometric method demonstrated superior diagnostic performance.