Background AVN is a common manifestation in patients with systemic lupus erythematosus (SLE), which can cause significant disability. Nevertheless, the exact pathogenetic mechanism has not been clarified.
Objectives To identify the risk factors for the development of avascular necrosis (AVN) and predictors for total hip replacement (THR) of the systemic lupus erythematosus (SLE) patients in Korea.
Methods The medical records of 1051 patients with SLE were reviewed and 73 patients with AVN were identified. Among them, 64 patients were eligible for the analysis. Sixty-four age-and sex-matched SLE patients without apparent AVN were included as disease controls. The risk factors for development of AVN were examined by logistic regression analyses. The predictors for THR were determined by Cox proportional hazards regression analyses.
Results Among 64 patients with AVN, 59 had AVN of the hip and 36 underwent THR. Independent risk factors for the development of AVN included cushingoid feature (OR 21.792, P=0.005), use of cyclophosphamide (OR 2.779, P=0.03) and azathioprine (OR 2.662, P=0.023). In Cox proportional hazards model, only advanced radiological stage of AVN (Association for Research on Osseous Circulation (ARCO) stage) was a statistically significant predictor for THR. In subgroup analysis with stage I-III AVN, multivariate Cox regression analysis showed NPSLE (HR 6.295, P= 0.001) and cumulative prednisolone dose in the first 6 months after AVN diagnosis >0.9g (HR 3.238, P= 0.034) were independent predictors.
Conclusions The advanced ARCO stage at the onset of AVN is an independent risk factor for THR in SLE patients with AVN. In ARCO stage I-III AVN, patients with NPSLE and patients who received more than 0.9g of prednisolone during the first 6 months after AVN diagnosis are likely to undergo THR.
Disclosure of Interest None Declared