Coronary arterial age for mortality prediction and risk reclassification in SCORE COVID-19 registry: When vascular age runs faster or slower than chronological age

Background: Coronary arterial age (CAA), derived from coronary artery calcium (CAC) percentiles from the Multi-Ethnic Study of Atherosclerosis (MESA), reflects vascular biological ageing. Its prognostic role in acute settings such as COVID-19 remains unclear. Methods: We analysed 1482 hospitalized patients from the multicentre SCORE-COVID registry undergoing chest CT. CAA was estimated from CAC percentiles; ΔAge was defined as CAA minus chronological age. A calcium-adjusted biological age (BioAge) was also assessed. The primary endpoint was 30-day all-cause mortality. Results: Chronological age and CAA showed similar discrimination (AUC 0.76 vs 0.74; P = .466) and were independently associated with mortality and increased stepwise across ΔAge strata. CAA mainly improved specificity by down-classifying survivors. While no significant interaction was observed between CAA and the 4C score, ΔAge significantly re-stratified mortality risk among patients at high 4C risk. Conclusions: CAA demonstrated prognostic performance comparable to chronological age for short-term mortality in COVID-19 and added clinically relevant information on vascular ageing. BioAge meaningfully refined risk stratification among patients at high clinical risk, supporting its use as an adjunctive biomarker whenever chest CT imaging is available.