AB0559 ASSOCIATED FACTORS AND PREVALENCE OF OSTEONECROSIS IN A COHORT STUDY IN PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) FROM HOSPITAL DEL MAR/PARC DE SALUT MAR

Background: Although the pathophysiology of osteonecrosis (ON) is not completely well-understood, it is likely the result of multiple combined effects such as environment, metabolic or genetic factors. Clinical presentation of ON may be silent or may appear in a variable range of gradual-onset pain. The prevalence of ON in patients with SLE varies according to whether the lesions are symptomatic or asymptomatic. Corticosteroid therapy (CT) has been recognized as a main risk factor to develop ON. Nevertheless, it looks like ON is more frequent in patients with SLE than in any other disease requiring systemic CT, which suggests that the use of corticosteroids may not be the only risk factor in those patients. Objectives: To evaluate the prevalence of ON and to determine the association between ON and other variables such as sociodemographic factors, cardiovascular risk factors, SLE symptoms, autoimmunity, treatment received and disease activity in patients with SLE from Hospital del Mar. Methods: 177 medical records were reviewed. Inclusion criteria included patients with SLE that met at least 4 of 11 ACR-LUPUS criteria revised in 1982 and updated in 1997. We identified six ON cases. The ON variable was evaluated by nuclear magnetic resonance in symptomatic patients. Afterwards, we matched ON patients with controls according to age and gender in a 1:2 proportion. A bivariate descriptive analysis between cases and controls was made including demographic and clinical variables, cardiovascular risk factors and treatment received. The association between ON and the previously mentioned variables was evaluated by Fishers Exact test and Chi-square test. Results: The prevalence of ON was 3.4% (CI 95%: 0.01% - 0.07%), lower than that described in other series. We found statistical significance association between ON and arterial hypertension (patients with ON and hypertension: 62.5% vs patients with ON without hypertension: 10%; p-value 0.043), as well as between ON and CT evaluated by its presence in the last hospital follow-up (patients with ON under CT: 100% vs patients with ON without CT: 20%; p-value 0.025). The association between ON and the use of corticosteroid pulse therapy (CPT) was also statistical significance (patients with ON who received CPT: 80% vs patients with ON who did not receive CPT: 15.3%; p-value 0.022). Finally, we found a marginal association, although relevant, between ON and the SLICC damage index (p-value 0.057) (Table/Fig-1). Conclusion: We found a statistical significance association between ON and hypertension (classical known cardiovascular risk factor) as well as between ON and CT (in the last visit) and the use of CPT (risk factor known as an etiological agent in ON). We did not find a statistical significance association between ON and lupus disease activity (SLEDAI), but a trend to statistical significance was noticeable with respect to the accumulated irreversible damage on lupus disease (SLICC). In order to confirm the results obtained, it is necessary to carry out other studies, with a larger sample and a longer follow-up period. Disclosure of Interests None declared