Takayasu's arteritis (TAK) is a rare chronic granulomatous vasculitis involving the aorta and/or its main branches, which, in severe cases, can lead to dilatation of the affected vessels, aneurysms, arterial entrapment, wall thickening, lumen narrowing, secondary ischemic organ dysfunction, and death [[1], [2], [3], [4]]. The 10-year mortality rate of patients with TAK is 3.9-10.0%, which is approximately two to four times higher than the healthy people [[5], [6], [7], [8], [9]]. Patients with TAK (50-96%) experience disease relapse within five years. Recurrence is a sign of increased disease activity and a major cause of organ damage and poor prognosis [[10], [11], [12], [13]]. Childhood-onset Takayasu arteritis (cTAK) has an insidious onset, lacks specific clinical symptoms, is difficult to diagnose at an early stage, and delayed treatment can lead to severe organ dysfunction, posing a serious threat to children's lives and health [3,14,15]. cTAK is more likely to cause systemic inflammation and extensive vascular disease than that for adult-onset TAK (aTAK), both of which are prone to relapse and cumulative damage [16]. Our team compared clinical features, vascular involvement, disease activity, and management between Chinese patients with cTAK and aTAK and similarly found that cTAK patients had more severe disease and inflammation [17].

Due to the rarity of cTAK, there is a paucity of prognostic data globally, with only small cohort studies [4,[16], [17], [18], [19], [20], [21], [22], [23], [24]], three of which involved analysis of risk factors associated with poor prognosis [4,16,18]. These studies showed that sex, age at set, C-reactive protein (CRP) and some symptoms were associated with prognosis [4,16]. However, these studies has some limitations. The age range of cTAK onset was wide, with a certain proportion of patients with infantile onset, while previous prognostic studies had been dominated by adolescent children. The results of a study by a research team from Nanjing Children's Hospital in China showed that the mortality rate of cTAK patients in infancy was as high as 40% [18]. Therefore, this group of patients cannot be ignored. Above all, there were no models for predicting cTAK patients at high risk with poor prognosis. Biological disease-modifying antirheumatic drugs (bDMARDs) can improve the prognosis of patients with cTAK [24], therefore, this multicenter cohort study was conducted to analyze the poor prognosis of patients with cTAK and develop a prediction model to provide a scientific basis for stratified management.