OBJECTIVES: To explore the outcomes among patients treated with TAVI (transcatheter aortic valve implantation) in the COMPARE-TAVI 1 trial by age groups and sex. DESIGN: Cohort study. SETTING: Three Danish university hospitals. PARTICIPANTS: Patients treated with TAVI in the COMPARE-TAVI 1 trial (N=1030), 60 (5.8%), 337 (32.7%), 592 (57.5%) and 41 (4.0%) were in the four age groups, < 70, 70-79, 80-89 and 90+ years while 414 (40.2%) and 616 (59.8%) were of female and male sex. INTERVENTIONS: Transfemoral TAVI with balloon-expandable valves (Sapien or Myval) performed between June 2020 and November 2023. OUTCOME MEASURES: Post hoc analyses of trial secondary outcomes that include end-point committee-adjudicated outcomes. RESULTS: In the four age groups, 1-year mortality rates were 8.3%, 5.6%, 5.6% and 7.3% while it was 5.8% in both sexes. Across the four age groups, 1-year stroke rates were 6.7%, 1.8%, 3.2% and 4.9%, and 5.1% among females and 4.7% among males. In the four age groups, 1-year new pacemaker rates were 7.5%, 15%, 19% and 13% while it was 15% among females and 18% among males. Females had smaller annuli than males and their gradients were higher and the effective orifice area lower after TAVI but their frequency of prosthesis-patient mismatch was similar at 1 year. CONCLUSION: While comorbidity levels varied between groups, clinical outcomes were similar across age groups and between sexes. TRIAL REGISTRATION NUMBER: NCT04443023.