Thrombocytopenia and disease outcomes in a cohort of patients with systemic lupus erythematosus. A post hoc analysis of the COMOSLE-EGYPT study

Abstract

Background: Thrombocytopenia ranges from 20% to 40% in patients with systemic lupus erythematosus (SLE). It is usually associated with severe disease manifestations and worse disease outcomes.

Aim of the study: To identify the frequency of thrombocytopenia in a cohort of Egyptian patients with SLE and to examine the relationship of thrombocytopenia with various disease manifestations and disease outcomes.

Methods: Data on 902 SLE patients were collected, including demographics, clinical, laboratory, immunological findings, and medications. SLE Disease Activity Index (SLEDAI) at baseline, last visit, and Systemic Lupus International Collaborating Clinics/ACR Damage Index (SLICC) were calculated. A comparison was done between patients with thrombocytopenia (group I) and patients without (group II) regarding different disease parameters. Regression analysis was done to examine if thrombocytopenia is a predictor of worse disease outcomes.

Results: Thrombocytopenia was found in 33% of our cohort. Longer disease duration was observed in group I compared to group II (p value = .01). As regards clinical manifestations, significantly higher frequencies of constitutional manifestations, anemia, arterial thrombosis, pulmonary hypertension, cardiac manifestations, neurological manifestations, gastrointestinal tract (GIT), and hepatic manifestations were detected in group I compared to group II. The disease damage index was detected to be significantly higher in group I as compared to group II (p value < .001). Mortality was higher in group I (p value < .001). Although it was found that antiphospholipid antibodies (APL) were associated with thrombocytopenia and their presence resulted in higher damage (p value: .001), the presence of thrombocytopenia even in patients with negative APL antibodies was associated with higher damage and mortality. Apart from thrombocytopenia, the male gender was also found to be an independent risk factor for mortality.

Conclusion: Thrombocytopenia was associated with more organ damage and higher mortality in SLE patients with or without APL antibodies. SLE patients with thrombocytopenia have a 3.4 times higher risk of mortality than patients without thrombocytopenia. Apart from thrombocytopenia, the male gender was also found to be an independent risk factor for mortality.

Keywords: SLE; damage; mortality; thrombocytopenia.