An Ensemble Marker: Implication Testing of Telangiectasia in Systemic Sclerosis

Telangiectasia — visible dilated superficial blood vessels on skin and mucous membranes — affects approximately 40–60% of SSc patients and scores 2 points in the 2013 ACR/EULAR classification criteria. Telangiectasia is also a component of the DETECT algorithm for pulmonary arterial hypertension (PAH) screening. Four implications are commonly stated or implied: that lcSSc subtype, anticentromere antibody (ACA), long disease duration, and telangiectasia itself imply PAH. Using the PAC-bound implication testing framework (Ritschel & Claude, 2026), we evaluated these implications in a synthetic SSc cohort (n=800) calibrated to the Zhang EUSTAR study (2015) and DETECT validation data. All four implications received TRENDING verdicts (chi-squared significant, violation rates 30–86%). No implication achieved MODERATE or STRONG. Using the PAC-bound implication testing framework (Ritschel & Claude, 2026), we evaluated these implications in a synthetic SSc cohort (n=800) calibrated to the Zhang EUSTAR study (2015) and DETECT validation data. All four implications received TRENDING verdicts (chi-squared significant, violation rates 30–86%). No implication achieved MODERATE or STRONG. The key finding is that telangiectasia PAH has an 86.1% violation rate — PAH affects only⇒ ~14% of telangiectasia-positive patients. This quantifies why telangiectasia alone is insufficient for PAH screening and supports the DETECT algorithm's multi-feature approach. The consistent TRENDING pattern identifies telangiectasia as an ensemble marker: its clinical value comes from combination with other features, not from individual implication strength. This paper closes the five-paper CREST series and together with Papers 01–04 provides the first systematic implication-strength evaluation of all five CREST features in SSc. Part of the CREST Implication Testing Series. Code: https://github.com/glenritschel/crest-implication-testing Implication verdicts: lcSSc Telangiectasia: TRENDING (37.5%) | ACA Telangiectasia: ⇒⇒TRENDING (30.5%) | Long duration Telangiectasia: TRENDING (36.9%) | Telangiectasia ⇒ PAH: REJECTED (86.1%)