Systemic lupus erythematosus in a multiethnic US cohort (LUMINA): XXIV. Cytotoxic treatment is an additional risk factor for the development of symptomatic osteonecrosis in lupus patients: results of a nested matched case–control study

Background: Osteonecrosis is common in systemic lupus erythematosus (SLE) and often disabling. The role of glucocorticoids in its development is well known. Objective: To explore other possible risk factors for osteonecrosis in SLE. Methods: A nested matched case–control study undertaken in the context of a large, longitudinal, multiethnic lupus cohort (LUMINA), currently formed of 571 SLE patients meeting American College of Rheumatology criteria. All those developing symptomatic osteonecrosis after the diagnosis of SLE were considered cases. Two controls matched for age, disease duration, ethnicity, and centre were selected for each case. Cases and controls were compared by univariable analyses using selected variables. Variables with p