Objective: To clarify whether age at the time of the initial administration of corticosteroids is a risk factor for corticosteroid-associated osteonecrosis in children with systemic lupus erythematosus (SLE), using magnetic resonance imaging (MRI).
Methods: From 1986 to 2007, MRI was used to prospectively study 676 joints, including 72 joints (36 hips and 36 knees) in 18 pediatric patients with SLE (<15 years old), 100 joints (50 hips and 50 knees) in 25 adolescent patients with SLE (15-20 years old), and 504 joints (252 hips and 252 knees) in 126 adult patients with SLE (>20 years old), beginning just after corticosteroid administration, for at least 1 year. The followup rate was 100%.
Results: In pediatric patients, osteonecrosis developed in 4 joints (6%; all hips). In adolescent patients, osteonecrosis developed in 49 joints (49%; 18 hips and 31 knees). In adult patients, osteonecrosis developed in 207 joints (41%; 95 hips and 112 knees). The rate of osteonecrosis was significantly lower in pediatric patients than in adolescent or adult patients (P = 0.0001). Logistic regression analysis revealed that adolescent and adult patients had a significantly higher risk for osteonecrosis compared with pediatric patients, with an odds ratio of 10.3 (P < 0.0001). The youngest patients with osteonecrosis in the hip and knee were 14.9 years old and 15.5 years old, respectively. Osteonecrosis did not develop in patients younger than age 14 years.
Conclusion: Our results suggest that age at the time of the initial administration of corticosteroids is associated with osteonecrosis in pediatric patients with SLE.