In longitudinal autoimmune cohorts, a model that combines baseline-referenced heart rate, heart-rate variability, oxygen saturation, step count, and Bayesian change-point concordance will identify symptomatic or inflammatory flares earlier than symptom diary review alone. The primary test should be a prospective daily wearable-plus-survey study in which the wearable model is evaluated against diary-only review using lead time to flare detection, calibration slope, and time-dependent AUC. The key falsifiable prediction is that multi-channel concordance adds measurable lead time after adjustment for baseline activity, glucocorticoid dose, and pre-existing autonomic dysfunction. Prior studies already show that wearable metrics shift before rheumatoid arthritis and inflammatory bowel disease flares, and HRV is altered in lupus disease activity. References: Sharma P et al. Sci Rep. 2025. DOI: 10.1038/s41598-025-29748-y; Hirten RP et al. Gastroenterology. 2025;168(5):939-951.e5. DOI: 10.1053/j.gastro.2024.12.024; Thanou A et al. Arthritis Res Ther. 2016;18(1):197. DOI: 10.1186/s13075-016-1087-x.