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DIGITAL HEALTH: This smartphone App can estimate blood pressure with accuracy

May 22, 2023
DIGITAL HEALTH: This smartphone App can estimate blood pressure with accuracy
A snip from the Digital Medicine journal with insets of Ifakara Health Institute scientists, Dr. Honorati Masanja and Dr. Getrud Mollel, who both contributed to the study and publication. GRAPHIC | IFAKARA/KMC.

A novel tool in the digital health world – OptiBP can estimate blood pressure (BP) with accuracy, scientists have confirmed. Scientists from Ifakara Health Institute and partner institutions arrived at the conclusion after assessing accuracy of the smartphone application for estimating BP in a multisite study held in Tanzania, Bangladesh and South Africa.

The study, whose results were published in the Digital Medicine journal recently, was conducted in Gaibandha, Bangladesh and Ifakara, Tanzania for general populations, and Kalafong Provincial Tertiary Hospital, South Africa for pregnant populations – based on guidance from the International Organization for Standardization (ISO) 81,060–2:2018 for non-invasive BP devices.

“OptiBP demonstrated accuracy against ISO standards in study populations, including pregnant populations,” the scientists say, noting however that a similar level of accuracy couldn’t be demonstrated in Bangladesh for “systolic” BP.

In response, the scientists recommend further research is needed to improve performance across different populations and integration within health systems. “These results expand on the findings from the studies conducted in Switzerland and indicate satisfactory performance in certain populations while highlighting the need for further algorithm refinements to ensure reliability for clinical use.”

Data for this multisite study were collected from November to mid-December 2021 across all three sites involving 160 consented individuals aged 18–80 years.

Ifakara scientists behind this study
Ifakara scientists who contributed to the study and publication include Dr. Honorati Masanja, Dr. Getrud Mollel and Charles Festo. Contributors from Ifakara partner institutions include: Valerie Vannevel and Tsakane Hlongwane from the South African Medical Research Council Maternal and Infant Health Care Strategies Unit, South Africa.

Others are: Hasmot Ali and Kaniz Fahmida from The JiVitA Maternal and Child Health and Nutrition Research Project, Bangladesh; Tigest Tamrat, María Barreix, Hedieh Mehrtash, Ronaldo Silva, Soe Soe Thwin, ”¶zge Tunçalp, and Garrett Mehl from the World Health Organization (WHO), Switzerland; and Kelsey Alland and Alain Labrique from the Johns Hopkins Bloomberg School of Public Health, USA.

Why worry about undetected, unmonitored hypertension?
Undetected and unmonitored hypertension carries substantial mortality and morbidity, especially during pregnancy. While smartphone-based tools present opportunities for addressing health system challenges, the diversity of the participants is a critical factor for studies evaluating these technologies that rely on algorithms, say the scientists.

“To our knowledge, this is one of the first studies on algorithm-based blood pressure estimation applications conducted in both urban and rural contexts of low- and middle-income settings, where data on medical device validation studies is limited,” claim the scientists.

On the factor of inclusion during the initial design of new technology such as recent developments in machine learning and algorithm development, the scientists object to the lack of diversity in training data and instead suggest the inclusion of affected populations to avoid biases among groups.

“This [diversity] is particularly important as such types of technologies, known as software as a medical device, or the use of software used for medical purposes without being part of a hardware medical device, use data and algorithms to provide clinical inputs.”

According to the scientists, the study contributes to the emerging body of literature on software used for medical purposes and represents one of the several studies to generate evidence using ISO guidance.

“Considering the novelty of this technology, future research is still needed to expand understanding on the performance of the application, as well as the health system implications of introducing this innovation across different cadres of health workers in facility and community settings, and to individuals directly as part of a self-care intervention approach.”

About the OptiBPTM
The OptiBP has been identified by the WHO as an innovative health technology for low-resource settings with a potential innovation for further exploration. The device does not require external integrations or procurement of equipment beyond a smartphone as its application leverages the smartphone camera to record optical pulse waves derived from blood volume changes at the fingertip.

>> Read full article: https://www.nature.com/articles/s41746-023-00804-z#Sec2