This nationwide observational cohort study compares the risk of major adverse cardiovascular events (MACE) and territory-specific arterial complications between patients with incident Takayasu arteritis and matched general-population controls, and identifies determinants of MACE within the Takayasu arteritis population, including cumulative glucocorticoid exposure, using the French National Health Data System (SNDS).

Study Design and Data Source This is a retrospective nationwide cohort study using the SNDS database covering approximately 99% of the French population. All patients aged 15 to 60 years with an incident hospital diagnosis of Takayasu arteritis (ICD-10 M31.4, recorded as a principal, related, or associated diagnosis; validated algorithm with positive predictive value 93.9%) between 2010 and 2024 were identified and matched without replacement to up to four general-population controls Statistical Analysis Cumulative incidence was estimated as one minus the Kaplan-Meier estimate, with 95% confidence intervals. Hazard ratios comparing patients with Takayasu arteritis to matched controls were estimated from Cox proportional-hazards models stratified on the matched set. For non-fatal outcomes, competing-risk analyses treating death as a competing event were performed (Fine-Gray subdistribution hazard ratios and Aalen-Johansen cumulative incidence functions). Within the Takayasu arteritis cohort, cumulative prednisone-equivalent glucocorticoid dose was modelled as a time-dependent covariate in multivariable Cox models adjusted for cardiovascular and disease-related factors.

Outcomes The primary outcome was the first major adverse cardiovascular event (MACE), a composite of coronary event (myocardial infarction or unstable angina), ischemic stroke, or all-cause death. Secondary outcomes included the individual MACE components and territory-specific arterial events: aortic events, visceral artery events, and major adverse limb events.

Regulatory Compliance This study was conducted using the SNDS through the permanent access granted to Assistance Publique - Hôpitaux de Paris (AP-HP), in accordance with French Decree No. 2016-1871 and French Public Health Code (Art. R. 1461-13 and 14). The study was registered in the AP-HP internal registry of research projects before initiation. In compliance with the GDPR and French regulations, individual informed consent was not required as all data were fully anonymized

Inclusion Criteria:

Age 15 to 60 years Cases: incident hospital diagnosis of Takayasu arteritis (ICD-10 M31.4) recorded as principal, related, or associated diagnosis between 2010 and 2024 Cases matched 4:1 to general-population controls (exact on sex and region; calipers on year of birth and propensity-score logit) Controls: alive and active in the database at the index date (≥1 reimbursed contact in the prior 365 days), residing in the same region, with no recorded Takayasu arteritis diagnosis

Exclusion Criteria:

Cases who could not be matched to at least four eligible general-population controls Age outside the 15 to 60 years range at the index date

Patients aged 15 to 60 years hospitalized for incident Takayasu arteritis in France identified from the SNDS database, together with up to four matched general-population controls per case.