[Characterization of a Portuguese population with systemic lupus erytematosus]

To characterize systemic lupus erythematosus (SLE) in Portuguese patients and to identify differences in diseases expression related to sex and ethnicity.

Retrospective cohort analysis of patients with SLE followed at five Rheumatology Departments between 1976 and 2006. Demographic data, diseases manifestations, medications used, co morbidity and damage scores were recorded.

Five hundred forty four patients were studied, 93% female, 89% Caucasians, with an average age at disease diagnosis of 35 years. The most frequent clinical features were musculoskeletal (91%), cutaneous and mucous membrane (90%) and the hematological involvement (58%). Renal diseases and serositis occurred more often in males while myositis was more common in black patients. Immunological features included the presence of anti-nuclear antibodies in 99% of the patients, anti-DNA (76%) anti-SSA (33%), anti-SSB (20%), anti-RNP (26%), anti-Sm (22%), anticardiolipine (31%) and lupus anticoagulant (21%). Anti-SSA, anti-RNP, and anti-Sm antibodies were significantly more prevalent among black patients. The presence and severity of damage measured by SLICC/ACR was similar between sexes and ethnicities. In multivariate analyses diseases duration and the presence of hypertension showed a positive association, while educational and antimalarials were negatively associated with the presence of damage.

In this cohort of Portuguese patients SLE present clinical features similar to those observed in other predominantly Caucasian populations, albeit a higher prevalence of anti-RNP and anti-Sm antibodies was observed. Some particular features were associated with male sex and African ethnicity. Some socio-demographic and clinical variables were associated with damage accrual.