RISK-FACTORS FOR AVASCULAR BONE NECROSIS IN SYSTEMIC LUPUS-ERYTHEMATOSUS

Objective. To study the predictive factors for avascular necrosis (AVN ) of bone in patients with systemic lupus erythematosus (SLE). Method. The records of 38 SLE patients who developed clinically apparent AVN during the course of their disease were reviewed. Information on clini cal presentation, corticosteroid usage and autoantibody profiles was o btained, and comparison was made between these patients and 143 consec utive control SLE patients who did not have AVN. Results. The point pr evalence of AVN in our SLE population was 12%. Patients with AVN. when compared with controls, had a significantly higher incidence of neuro logical disease (39% cs 14%; P < 0.001) and Cushingoid body habitus af ter steroid treatment (79% vs 53%; P = 0.004). The highest cumulative prednisolone dose in 1 and 4 months was significantly higher in the AV N group than the controls (1.8 vs 1.1 and 4.5 vs 2.8 g, respectively; P < 0.01 in both) and showed a linear trend with the incidence of AVN (chi(2) test for trend, P < 0.01 in both). Lupus anticoagulant was ass ociated with AVN (P = 0.02, odds ratio 2.88 [1.14-7.28]). Logistic reg ression analysis revealed that the highest cumulative prednisolone dos e administered in 4 months, the maximum and mean daily prednisolone do sage, and the lupus anticoagulant were independent risk factors for AV N. Conclusions. Corticosteroid remains the major predisposing factor f or AVN in SLE. Patients who require an initial high-dose steroid for d isease control are at risk of AVN, especially if they are positive for the lupus anticoagulant or develop Cushingoid habitus after steroid t reatment. High-risk patients should be closely monitored so that early AVN can be diagnosed by sensitive techniques such as magnetic resonan ce imaging and radioisotope bone scanning.