Disease activity as a major risk factor for osteonecrosis in early systemic lupus erythematosus

Abstract

This study Identifies the possible risk factors for osteonecrosis (ON) in a homogenous group of early system lupus erythematosus (SLE). Forty-six consecutive SLE patients (<5 years duration) followed at the Lupus Clinic, were enrolled between 2004 and 2005. An extensive clinical and laboratory evaluation using a standard electronic protocol established since 1999, including osteonecrosis symptoms and appropriate magnetic resonance imaging (MRI), were carried out at 1—6 months intervals. All other asymptomatic for osteonecrosis patients at study entry underwent MRI. ON confirmed by MRI was found in 10 of 46 patients (22%). Age, disease duration, clinical vascular features, frequency of thrombophilia and hypofibrinolysis factors and the lipoprotein profile were comparable in patients with and without osteonecrosis ( P > 0.05). Remarkably, the frequency of patients with system lupus erythematosus disease activity index (SLEDAI) ≥8 in the previous year of osteonecrosis clinical diagnosis was significantly higher when compared to patients without this manifestation (60.0% versus 19.4%, P = 0.011), supported by the higher glucocorticoid cumulative dose in the same period ( P = 0.045). In contrast, these two parameters evaluated in 13th—24th months preceding osteonecrosis diagnosis were similar in patients with and without osteonecrosis ( P > 0.05). In the logistic regression analysis only SLEDAI remained as an independent risk factor for ON (OR = 6.78, CI = 1.05—43.55, P = 0.04). Disease activity in the previous year of ON clinical diagnosis is the main predictor factor for the development of this complication in early SLE. Lupus (2007) 16, 239—244.