Predictive factors for symptomatic osteonecrosis in patients with systemic lupus erythematosus.

Objective: To analyze predictive factors for the development of osteonecrosis (ON) in a large cohort of patients with systemic lupus erythematosus (SLE) followed in a single center.
Methods: A nested matched case control design was used. Patients with SLE who developed ON during followup were identified from the University of Toronto Lupus Clinic database. The diagnosis of ON was confirmed by either radiographs, bone scans, tomograms, or magnetic resonance imaging. A comparison group of patients with SLE without ON was selected from the same database, matched by year of birth. sex, and year of entry to the clinic to the patients with ON. Clinical, laboratory, and therapeutic factors thought to be relevant to the development of ON were compared between the 2 groups.
Results: Seventy patients with SLE developed ON in the course of followup at the clinic. In univariate analysis, arthritis was the only clinical feature predictive of the development of ON. Use of glucocorticosteroid therapy, dose and duration, as well as Cushingoid appearance and cytotoxic therapy were also predictive for the development of ON. Multivariate analysis revealed that glucocorticosteroid use, the presence of arthritis, and the use of cytotoxic medications remained significant.
Conclusion: Glucocorticosteroid therapy, the presence of arthritis, and use of cytotoxic medication are independent risk factors for development of ON in patients with SLE.