Progression of non-radiographic to radiographic axial spondyloarthritis: a risk model based on a chinese cohort study.

OBJECTIVES

To evaluate the progression from non-radiographic axial spondyloarthritis (nr-axSpA) to radiographic axial spondyloarthritis (r-axSpA) in a Chinese cohort, identify associated risk factors in both clinical and imaging arms, and enable risk stratification based on these factors.

METHODS

Overall, 572 patients with nr-axSpA were enrolled with a median follow-up of 5 years. Cox proportional hazard regression analyses were conducted to identify potential risk factors associated with the progression from nr-axSpA to r-axSpA in both clinical and imaging arms. A risk-scoring system was then developed by assigning each independent predictor a weight based on its regression coefficient. Patients were subsequently categorized into low-, medium-, and high-risk groups according to their cumulative scores.

RESULTS

By the end of follow-up, 40.2% of nr-axSpA patients had progressed to r-axSpA, more frequently in the imaging arm than in the clinical arm (56.1% vs. 17.4%, P < 0.001). Multivariate Cox regression analysis showed that unilateral grade II radiographic sacroiliitis and high disease activity (ASDAS-CRP > 2.1) were significant predictors of progression in both the imaging arm (HR = 2.00, 95% CI 1.40-2.86 and HR = 2.38, 95% CI 1.30-4.34, respectively) and the clinical arm (HR = 6.28, 95% CI 2.73-14.48 and HR = 3.68, 95% CI 1.08-12.51, respectively). HLA-B27 positivity (HR = 2.67, 95% CI 1.72-4.11) in the imaging arm and a family history of spondyloarthritis (HR = 2.72, 95% CI 1.18-6.28) in the clinical arm were associated with increased progression risk. Based on these factors, a predictive model classified patients into low-, medium-, and high-risk groups. In the imaging arm, the model achieved AUCs of 0.839, 0.777, and 0.807 for 3-, 5-, and 10-year progression rates, respectively; in the clinical arm, the corresponding AUCs were 0.660, 0.780, and 0.820.

CONCLUSIONS

In the imaging arm, nr-axSpA patients progress to r-axSpA more rapidly and frequently than those in the clinical arm. Risk factors include unilateral grade II sacroiliitis, high disease activity, HLA-B27 positivity, and SpA family history. A risk scoring system was developed for progression prediction and personalized management. Large-scale prospective multicenter studies are needed to validate its clinical utility across diverse populations.