Opportunistic coronary calcium progression on routine chest CT improves cardiovascular risk stratification in patients with inflammatory bowel disease: a multicenter study

Background: Patients with inflammatory bowel disease (IBD) have increased atherosclerotic cardiovascular risk that may be underestimated by conventional factors. Whether coronary artery calcium (CAC) progression adds prognostic value beyond baseline CAC in IBD is unclear. Methods: In this multicenter retrospective cohort, 467 IBD patients without known atherosclerotic cardiovascular disease underwent ≥2 routine non-contrast chest CT scans (mean interval 21.2 months). CAC progression was defined as incident CAC (0 to >0), absolute progression (0 < baseline <100 with annualized increase ≥10), or relative progression (baseline ≥100 with annualized increase ≥10%). Major adverse cardiovascular events (MACE) were the primary outcome; incident atrial fibrillation (AF) was secondary. Cox proportional hazard regression was utilized to estimate hazard ratios (HRs) for time to MACE regarding CAC progression. Incremental value was assessed by C-index and continuous net reclassification improvement (NRI). CAC progression was also associated with incident AF. Conclusions: Opportunistic CAC progression assessment from routine chest CT improves cardiovascular risk stratification in IBD beyond conventional factors and baseline CAC, including among patients with zero baseline CAC.