Smartphone-based measures as real-world indicators of functional status in advanced cancer patients

This study evaluated the feasibility of using smartphone-based metrics to monitor physical functioning and quality of life in patients with advanced gynecological cancers. We analyzed associations between gait (step count, cadence, stride acceleration) and measures of mobility (home time, distance traveled, number of significant locations visited) with patient-reported outcomes (PROMs).

We studied raw accelerometer and GPS data from smartphones over 180-days for 85 patients with advanced gynecologic cancers. We computed measures of gait and mobility from smartphone sensor data, and PROMs (performance status, health-related quality of life, physical functioning) from smartphone surveys at baseline, 30, 90, and 180 days. We assessed longitudinal associations of digital gait and mobility measures with PROMs using linear mixed-effects models, with attention to smartphone adherence and temporal trends.

Smartphone adherence was high: 83% of participants reported daily smartphone usage >1 hour; 74.1% had >16 hours of daily use. Gait measures, particularly step count and stride acceleration, were statistically associated with PROMs. Worsening patient-reported ECOG performance status corresponded to reduced step count (ECOG 3 vs. 0: -1837 steps/day, p<0.001), while higher PROMIS Physical Function was associated with step count increase (+72.64 steps/day per one-point increase, p<0.001). Mobility measures were less strongly associated with PROMs but provided complementary insights into patients' behavioral patterns.

Smartphone-based gait and mobility metrics offer robust, real-world insights into individuals' health statuses, providing a scalable, low-burden alternative to wearable devices. The high levels of smartphone use among participants underscore the feasibility of integrating this technology into routine oncology care.