Stability of watch-based blood pressure measurements analyzed by pre-post calibration differences

Recent advancements in smartwatch technology have introduced photoplethysmography (PPG)-based blood pressure (BP) estimation, enabling convenient and continuous monitoring of BP. However, concerns about accuracy and validation for clinical use persist. This study uses real-world data from a Samsung Galaxy Watch campaign to assess smartwatch-based BP measurements. The approach examines calibration stability by comparing average systolic BP (SBP) before and after calibration, identifying factors affecting stability through regression analysis. User-level strategies are suggested to mitigate calibration instability and emphasize guideline adherence. Notably, calibration instability is found to decrease during night-time measurements and when averaging multiple readings in the same time frame. Guideline adherence is vital, particularly for the elderly, females, and individuals with hypertension. The research enhances measurement reliability through extensive datasets, shedding light on calibration stability.