Systemic Lupus Erythematosus and Osteonecrosis: A Comparison of Patients with Single versus Multiple Joint Involvement

Objective: The purpose of this study was to determine the clinical and laboratory features associated with osteonecrosis of multiple (>/= 3) joints in systemic lupus erythematosus (SLE). Methods: We included all patients with SLE and osteonecrosis evaluated at our institution between January 1, 2000 and June 30, 2006. The patients were divided into three groups based on osteonecrosis of 1 joint, 2 joints and 3 or more joints. Clinical features, laboratory findings and therapies of patients in these groups were compared using Fischer’s exact test and rank sum tests. Results: Our study included 4 men and 37 women. Twelve patients (29.3%) had osteonecrosis of 1 joint, 16 patients (39%) had osteonecrosis of 2 joints and 13 patients (31.7%) had osteonecrosis of 3 or more joints. The only clinical feature of SLE significantly associated with osteonecrosis of 3 or more joints was central nervous system (CNS) disease (p = 0.01). The median cumulative and peak corticosteroid doses were similar in all 3 groups (p = 0.70 and p = 0.11 respectively). There were no differences in the frequency of anti-cardiolipin antibodies. Conclusions: History of CNS disease was the only variable associated with multiple joint osteonecrosis in patients with SLE. We found no association between corticosteroid doses and multiple joint osteonecrosis.