Evaluation of a novel mobile phone application for blood pressure monitoring: a proof of concept study

To provide information about the clinical relevance of blood pressure (BP) measurement differences between a new smartphone application (OptiBP (TM)) and the reference method (automated oscillometric technique) using a noninvasive brachial cuff in patients admitted to the emergency department. We simultaneously recorded three BP measurements using both the reference method and the novel OptiBP (TM) (test method), except when the inter-arm difference was > 10 mmHg BP. Each OptiBP (TM) measurement required 1-min and the subsequent reference method values were compared to the values obtained with OptiBP (TM) using a Bland-Altman analysis and error grid analysis. Among the 110 patients recruited, OptiBP (TM) BP values could be collected on 61 patients (55%) and were included in the statistical analysis. The mean of differences (95% limits of agreement) between the reference method and the test method were - 0.1(- 22.5 to 22.4 mmHg) for systolic arterial pressure (SAP), - 0.1(- 12.9 to 12.7 mmHg) for diastolic arterial pressure (DAP) and - 0.3(- 18.1 to 17.4 mmHg) for mean arterial pressure (MAP). The proportions of measurements in risk zones A-E were 86.9%, 13.1%, 0%, 0%, and 0% for MAP and 89.3%, 10.7%, 0%, 0%, and 0% for SAP. In this pilot study conducted in stable and awake patients admitted to the emergency department, the absolute agreement between the OptiBP (TM) and the reference method was moderate. However, when BP measurements were made immediately after an initial calibration, error grid analysis showed that 100% of measurement differences between the OptiBP (TM) and reference method were categorized as no- or low-risk treatment decisions for all patients. Trial Registration: ClinicalTrials.gov Identifier: NCT04121624.