Background: Avascular necrosis (AVN) has been reported in systemic lupus erythematosus (SLE) and most SLE patients suffer from this problem.
Objectives: To study the prevalence of AVN in Thai SLE patients and to determine the risk factors for developing AVN.
Methods: A retrospective study was performed, between January 1, 1995 and August 31, 2005, on patients over 15 years of age in Khon Kaen, Thailand.
Results: The medical records of 736 SLE patients were reviewed. The female to male ratio was 15.4:1. The prevalence of AVN was 8.8%. The average age at the time of AVN detection was 27 years (range, 18-54) and the average duration of disease 69 months (range, 12-112). All cases were AVN of the hip joint. The factors correlated with AVN included: long duration of disease, history of previous septic arthritis in the ipsilateral hip to the AVN development, hematological involvement, gastrointestinal involvement, arthritis and cutaneous vasculitis. After regression analysis, hematological involvement and long duration of disease were associated with AVN with a respective odds ratio of 3.13 (95% CI 1.13-8.54) and 1.01 (95% CI 1.00-1.02). Neither high-dose steroid nor antimalarial treatment were correlated with AVN in our study and 4.6% (n = 3) of patients had never received steroid therapy during the follow-up period.
Conclusion: Prevalence of symptomatic AVN was 8.8% in our SLE patients. A longer duration of disease and hematological involvement were associated with AVN development.