Innovations to address the burden of hypertension: Assessing accuracy of a smartphone application-based blood pressure estimation algorithm in Bangladesh, South Africa and Tanzania among general and pregnant populations

Abstract

Background: Undetected and unmonitored hypertension carries substantial mortality and morbidity, especially during pregnancy. Innovations have potential to address these challenges. We assessed the accuracy of OptiBPTM, a smartphone application for estimating blood pressure (BP), across diverse settings. Methods: The study was conducted in community settings: Gaibandha, Bangladesh and Ifakara, Tanzania for the general population, and Kalafong Provincial Tertiary Hospital, South Africa for pregnant populations. Based on guidance from the International Organization for Standardization (ISO) 81,060–2:2018 and global consensus statement, we compared BP measurements taken by two independent trained nurses on a standard auscultatory cuff to the BP measurements taken by a research version of OptiBPTM called CamBP. Results: For ISO criterion 1, the mean error was 0.5 ± 5.8 mm Hg for the SBP and 0.1 ± 3.9 mmHg for the DBP in South Africa; 0.8 ± 7.0 mmHg for the SBP and -0.4 ± 4.0 mmHg for the DBP in Tanzania; 3.3 ± 7.4 mmHg for the SBP and -0.4 ± 4.3 mmHg for the DBP in Bangladesh. For ISO criterion 2, the average standard deviation of the mean error per subject was 4.9 mmHg for the systolic BP and 3.4 mmHg for the diastolic BP in South Africa; 6.3 mmHg for the systolic BP and 3.6 mmHg for the diastolic BP in Tanzania; 6.4 mmHg for the systolic BP and 3.8 mmHg for the diastolic BP in Bangladesh. Conclusion: OptiBPTM demonstrated accuracy against ISO standards in study populations, including pregnant populations, except in Bangladesh for systolic BP (criterion 2). Further research is needed to improve performance across different populations and integration within health systems. Funding: This work was funded by the Bill and Melinda Gates Foundation (grant number OPP1201339) and the UNDP-UNFPA-UNICEF-WHO-World Bank Special Programme of Research, Development and Research Training in Human Reproduction (HRP), a cosponsored programme executed by the World Health Organization (WHO).