Background Hematologic involvement is common in patients with SLE. Thrombocytopenia and AIHA, prevalences of which have been reported as 10–40% and 5–10% respectively, have considerable impact on prognosis.
Objectives Herein, we aimed to investigate the frequencies of these hemocytopenias, their clinical and serological associations and effect on disease outcome in a large single centre cohort of patients.
Methods We analysed our cohort of 852 patients who fulfilled at least 4 of the ACR criteria for SLE. The data presented was the cumulative clinical and serological manifestations throughout the follow-up period. Hemolytic anemia was defined as a drop in hemoglobin accompanied by increased reticulocyte count, high serum lactate dehydrogenase and reduced haptoglobin levels in the presence of a positive Coombs' test. Thrombocytopenia was defined as a platelet count of <100x109/mm3. Demographic characteristics, clinical features, autoantibody profiles, damage and mortality data retrieved from the database were compared between patients with and without each hematological abnormality. The χ2 test, logistic regression and Kaplan-Meier survival analyses were used.
Results There were 93 (10.9%) patients with AIHA and 215 (25.3%) with thrombocytopenia. Patients with AIHA were significantly younger at diagnosis (27±13 vs 31±12, p<0.05) and had a significantly shorter disease duration (95±84 vs 118±85 mo, p<0.05). AIHA and thrombocytopenia were both associated with neuropsychiatric (NP) involvement (p<0.05) and associated with each other (p<0.05) and leukopenia (p<0.05). Comparison of patients with AIHA or thrombocytopenia to the rest of the cohort displayed significant associations with antiphospholipid syndrome (APS), anticardiolipin (aCL) antibodies and lupus anticoagulant (LA). In patients with thrombocytopenia the relationship with APS features, namely thrombosis and pregnancy morbidity, was stronger (p<0.001).
Compared to the rest of the cohort, more patients in both groups had organ damage and their mean SLICC damage score was significantly higher. Association to NP damage was discernible in both groups (p<0.05). In addition, damage in renal and cardiovascular domains and diabetes were more pronounced in patients with thrombocytopenia (p<0.001)
Kaplan Meier survival analysis showed that patients with AIHA had significantly reduced survival rates at 10 (94 vs 77%) and 20 (88 vs 77%) years (p<0.001). In the thrombocytopenia group, despite the lack of significant differences, there was a tendency for lower survival rates.
Conclusions We demonstrated that both AIHA and thrombocytopenia were associated with aCL antibodies, coexisting APS and NP involvement and damage in our cohort. There was a strong link between AIHA and thrombocytopenia. Patients with AIHA had a younger age at disease onset with reduced survival. No significant reduction in survival rates was observed in patients with thrombocytopenia. However, besides NP involvement, thrombocytopenia delineated a subgroup of patients with a higher renal and cardiovascular damage which perceivably can affect prognosis. Overall, AIHA and thrombocytopenia may predict a poorer outcome in patients with SLE.
Disclosure of Interest None declared