Assessing the usability and feasibility of a novel bone-specific activity-tracking app to help prevent osteoporosis in the real world at scale

Osteoporosis is a bone-wasting disease that makes bones thinner, weaker and more likely to break. Breaking bones in the hip and spine is painful, life-changing and costly to the NHS (currently £5.5 billion/yr), with cases expected to double by 2050 largely due to a growing ageing population. It is possible to avoid or delay getting osteoporosis, but other than general advice on nutrition or exercise, there is no support to help people strengthen their bones during everyday living across the lifespan. As osteoporosis affects one in two women over the age of 50 compared to one in five men, women are disproportionately impacted by the disease. In addition to being more common in women, osteoporosis and its consequences also affect people with lower incomes or less education more often, due to factors like poor nutrition, limited access to healthcare and lower awareness of bone health. When made aware of both their elevated risk and our research demonstrating that even modest bone-strengthening, impact activity can yield measurable benefits, women, and particularly those leading up to and after the menopause (40-60 years), express a strong demand for accessible interventions to improve their bone health before irreversible decline occurs. Short, sharp bursts of bone strengthening impact activity cannot be inferred from common metrics such as steps, distance, heart rate or calories. As no existing app or wearable accurately captures this specific activity, we identified a critical gap for a digital health tool that helps both men and women incorporate bone-strengthening impacts into their everyday lives. To address this gap, we developed a novel bone-specific activity-tracking algorithm that uses data from smartphones or wearable devices to detect and encourage users to monitor and increase bone-strengthening impact activity for themselves. Similar to the goal-oriented habit of tracking daily steps on pre-installed apps, common even among phone users who don’t actively engage in structured exercise, our algorithm is designed to support the formation of a simple, low-burden, goal-oriented habit focused on tracking small but important amounts of bone-specific impact activity accumulated throughout daily life. We initially incorporated this algorithm into an early-stage alpha-prototype app and tested its function with a small subset of users (n=25). We have now embedded this algorithm in a user-friendly beta-prototype app, which provides a platform for further proof-of-concept and value testing with a larger sample of end-users in a real-world setting. We now must assess how large groups of users, who differ in sex, age and deprivation, engage with the app and its potential to deliver sustained improvements to bone-strengthening activity habits. This will be achieved through a single work package where the usability of the app will be tracked in 410 users (men and women, aged 40-50 and 51-60, from areas with lower and higher levels of deprivation) over a 3-month period. The resulting data will determine how interested different user groups are in being recruited to a study like this, whether users engage meaningfully with the app (rate of user uptake and engagement; feasibility), the number of days users meet target impact scores and how these scores vary over time (rates of impact-target adherence). This evidence will rapidly de-risk further development by assessing the app’s viability for large-scale implementation, providing a clear go/no-go decision point.