aortic stenosis, aortic valve replacement, cardiac amyloidosis, hospitalization, death, Diseases of the circulatory (Cardiovascular) system, RC666-701

Background The coexistence of transthyretin cardiac amyloidosis (ATTR‐CA) and aortic stenosis (AS) is increasingly recognized, but the clinical consequences are unclear. We aimed to characterize clinical outcomes in AS plus ATTR‐CA compared with only AS or ATTR‐CA. Methods and Results In a retrospective cohort study, patients with AS only, ATTR‐CA only, or AS plus ATTR‐CA were identified using all‐payer claims data (2015–2021). Eligible patients had ≥1 claim for AS or cardiac amyloidosis (excluding light‐chain cardiac amyloidosis); were aged ≥60 years; and were continuously enrolled in medical plans for ≥6 months after diagnosis. Ad hoc subanalyses were conducted in patients with aortic valve replacement at first diagnosis (surrogate for severe AS). Of 355 430 eligible patients, 345 771 (97.3%), 8453 (2.4%), and 1239 (0.3%) were included in the AS‐only, ATTR‐CA–only, and AS–plus–ATTR‐CA cohorts, respectively; 41 312 (11.9%), 14 (0.2%), and 212 (17.1%) had aortic valve replacement. Two‐year mortality rates were 16.1% (95% CI, 15.9–16.2), 14.8% (95% CI, 13.9–15.7), and 19.2% (95% CI, 16.9–21.8) in the AS‐only, ATTR‐CA–only, and AS–plus–ATTR‐CA cohorts; heart failure hospitalization rates were 29.4% (95% CI, 29.2–29.5), 22.8% (95% CI, 21.9–23.8), and 48.7% (95% CI, 45.7–51.7). AS plus ATTR‐CA was associated with increased risk of death (HR, 1.3 [95% CI, 1.1–1.4]; P