Predictors of relapse in Takayasu arteritis

Background: Takayasu arteritis (TAK) is a large-vessel vasculitis with high relapse rate. Longitudinal studies identifying risk factors of relapse are limited. We aimed to analyze the associated factors and develop a risk prediction model for relapse. Methods: We analyzed the associated factors for relapse in a prospective cohort of 549 TAK patients from the Chinese Registry of Systemic Vasculitis cohort between June 2014 and December 2021 using univariate and multivariate Cox regression analyses. We also developed a prediction model for relapse, and stratified patients into low-, medium-, and high-risk groups. Discrimination and calibration were measured using C-index and calibration plots. Results: At a median follow-up of 44 (IQR 26-62) months, 276 (50.3%) patients experienced relapses. History of relapse (HR 2.78 [2.14-3.60]), disease duration <24 months (HR 1.78 [1.37-2.32]), history of cerebrovascular events (HR 1.55 [1.12-2.16]), aneurysm (HR 1.49 [1.10-2.04], ascending aorta or aortic arch involvement (HR 1.37 [1.05-1.79]), elevated high-sensitivity C-reactive protein level (HR 1.34 [1.03-1.73]), elevated white blood cell count (HR 1.32 [1.03-1.69]), and the number of involved arteries & GE;6 (HR 1.31 [1.00-1.72]) at baseline independently increased the risk of relapse and were included in the prediction model. The C-index of the prediction model was 0.70 (95% CI 0.67-0.74). Predictions correlated with observed outcomes on the calibration plots. Compared to the low-risk group, both medium and high-risk groups had a significantly higher relapse risk. Conclusions: Disease relapse is common in TAK patients. This prediction model may help to identify high-risk patients for relapse and assist clinical decision-making.