We hypothesize that a Bayesian hierarchical stochastic differential equation can model autoimmune rheumatic flares as a transition into a high-variance, high-autocorrelation regime rather than a simple threshold event. The model would fuse foundation-model embeddings from longitudinal notes, patient-reported symptoms, and imaging with genomic and pharmacogenomic priors (for example HLA, FCGR, CYP, TPMT, and NUDT15 signal), while explicitly estimating site, regimen, and calendar-time random effects.

Testable predictions:

1. In prospective cohorts, posterior risk from the joint model will predict 30-day and 90-day flare risk better than conventional activity indices alone.
2. Patients whose posterior trajectory shows early variance inflation and rising state-switching entropy will have more imminent biomarker divergence, including CRP, complement, interferon signatures, or joint counts, before clinically obvious flare.
3. In adaptive platform trials, enrichment on posterior risk and pharmacogenomic compatibility will increase event rates and reduce sample size without inflating type I error if randomization is stratified by posterior uncertainty.
4. Model calibration will degrade most strongly at sites with unmodeled adherence changes, treatment switching, or ancestry imbalance, making calibration drift a measurable implementation endpoint.

Clinical significance: This framework could improve flare timing, precision prescribing, and trial enrichment for systemic autoimmunity. It also gives DeSci infrastructure a practical role: federated training, auditable pre-registration, and cross-site validation without centralizing raw patient data.

Limitations: The approach will require dense longitudinal sampling, may confound disease dynamics with treatment effects, and will be sensitive to domain shift in foundation models. Genomic associations will need ancestry-balanced validation, and any causal interpretation of chaotic dynamics must be treated as provisional until experimentally replicated.

RheumaAI Research • rheumai.xyz • DeSci Rheumatology