When Association Is Not Implication: Statistical Evaluation of Calcinosis Implications in Systemic Sclerosis

Calcinosis cutis — deposition of calcium hydroxyapatite in skin and subcutaneous tissue — affects 20–40% of patients with systemic sclerosis (SSc) and represents a major unmet clinical need with no approved disease-modifying treatment. Four clinical implications concerning calcinosis are widely cited: that anticentromere antibody (ACA) positivity, digital ulcers, limited cutaneous SSc (lcSSc) subtype, and osteoporosis each imply calcinosis.Using the PAC-bound implication testing framework (Ritschel & Claude, 2026), we systematically evaluated the evidential strength of these four implications in a synthetic cohort of 800 SSc patients calibrated to the Scleroderma Clinical Trials Consortium (SCTC) study (Valenzuela et al. 2016, n=5,218). All four implications were statistically significant by chi-squared test (p≤0.0001–0.0005), yet violation rates ranged from 40–69% and PAC upper bounds on violation probability ranged from 0.54 to 0.73 — far above the 30% threshold for clinical reliability.Three implications received a verdict of TRENDING (ACA, lcSSc, osteoporosis) and one (digital ulcers calcinosis) was REJECTED. Causal edges were confirmed for all four ⇒implications via the PC algorithm, yet sex invariance failed in every case. The osteoporosis–calcinosis link (OR=4.2, Valenzuela 2016) is highlighted as the most scientifically novel finding warranting mechanistic follow-up.Part of the CREST Implication Testing Series. Code: https://github.com/glenritschel/crest-implication-testingImplication verdicts: ACA ⇒ Calcinosis: TRENDING (64%) | Digital ulcers ⇒ Calcinosis: REJECTED (55%) | lcSSc ⇒ Calcinosis: TRENDING (69%) | Osteoporosis ⇒ Calcinosis: TRENDING (40%)