Non-corticosteroid risk factors of symptomatic avascular necrosis of bone in systemic lupus erythematosus: A retrospective case-control study.

OBJECTIVE Avascular necrosis of bone (AVN) is an important complication of systemic lupus erythematosus (SLE). Corticosteroid therapy has been underlined as a main risk factor for osteonecrosis. However, AVN development in patients who have never received corticosteroid and the absence of AVN in the majority of the patients, who received corticosteroid, propose a role for non-corticosteroid risk factors in AVN development. METHODS This case-control study included two subsets: oral corticosteroid (66 AVN and 248 non-AVN patients) and pulse-therapy subset (39 AVN and 312 non-AVN patients) who have attended our Lupus clinic from 1979 to 2009. Patients received similar cumulative dose corticosteroid, equal maximum dose and 1-year maximum dose of corticosteroid. The demographic data (including sex, age of disease onset, age at the diagnosis of AVN), organs involvement, SLE Disease Activity Index (SLEDAI), Systemic Lupus International Collaborating Clinics/American College of Rheumatology-Damage index (SLICC/ACR-DI), number of disease flare ups were compared between two subsets. RESULTS The mean age of SLE onset was younger (P value = 0.04) in the AVN patients. In oral corticosteroid subset, malar rash (P value < 0.001) and oral ulcer (P value = 0.003) were seen more frequently in non-AVN patients, whereas psychosis (P value = 0.03) was significantly more prevalent AVN subset in oral corticosteroid subset. In corticosteroid pulse subset, no significant difference in clinical features was noted. CONCLUSION In oral corticosteroid subset, younger age of disease onset and psychosis were significantly associated with AVN, whereas malar rash and oral ulcer showed negative association AVN.