Near-Universal but Not Implied: Statistical Implication Testing of Raynaud Phenomenon in Systemic Sclerosis

Raynaud phenomenon (RP) affects over 95% of patients with systemic sclerosis (SSc) and is typically the earliest disease symptom. Four clinical implications are frequently stated: that abnormal nailfold capillaroscopy, SSc-specific autoantibodies (ACA or anti-Scl70), and late capillaroscopy pattern each imply RP or severe RP; and that digital ulcers imply severe RP. Using the PAC-bound implication testing framework (Ritschel & Claude, 2026), we evaluated these four implications in a synthetic SSc cohort (n=800) calibrated to the VEDOSS registry (Mihai et al. 2021, n=764). Two implications received MODERATE verdicts: abnormal capillaroscopy Raynaud (violation rate 1.8%, PAC