Pb2616: systemic lupus erythematosus related immune thrombocytopenia: a characteristic clinical fenotipe

Topic: 32. Platelet disorders Background: Systemic lupus erythematosus (SLE) is an autoimmune disease with a wide variety of manifestations, including immune thrombocytopenia (ITP). ITP has been described in 7-40% of patients with SLE. Aims: To determine the prevalence of ITP within the cohort of patients with SLE from Hospital del Mar and to identify those risk factors associated with the development of ITP. Methods: A retrospective case-control study was conducted in which 407 medical records of patients with SLE were reviewed: 34 patients had developed ITP (cases) and were randomly matched by sex and age with 2 controls with SLE without ITP. Results: The prevalence of ITP in our cohort was 8.35% and was diagnosed at an age of 43.14 ± 17.11 years (mean ± standard deviation) (see table 1). No statistically significant differences in demographic variables were found between groups. At the diagnosis of SLE, controls had a higher prevalence of arthritis (p = 0.02), while cases had a higher proportion of hemolytic anemia (p = 0.04). Over the course of the disease, cases had a higher presence of antiphospholipid syndrome (APS) antibodies (lupus anticoagulant, p = 0.01; anticardiolipin, p = 0.044; anti-β2GP1, p = 0.003). In turn, cases obtained a significantly higher Systemic Lupus International Collaborating Clinics damage index (SLICC) than controls (p = 0.02). Regarding treatment, cases received mycophenolate (p = 0.02) and azathioprine (p = 0.045) more frequently than controls.At ITP events (see table 2), 13 (38.24%) cases developed a severe form of the condition, and 6 (17.65%) had less than 10,000 platelets/mm3. Among these cases, 12 (35.29%) had a hemorrhagic manifestation, with ecchymosis being the most common. Additionally, 18/34 (52.94%) of cases had ITP recurrences, with a median of 2 recurrence episodes (min 1; max 6). Of the 34 cases, 6 (17.65%) did not require treatment. Corticosteroids were the most common ITP treatment prescribed, rituximab was used in 7/34 (20.58%) cases and splenectomy in 2/34 (5.88%). 18/34 (52.29%) had a complete response, and the median number of treatments was 2 (min 0; max 6). Table 2: ITP characteristics and ITP treatments - VARIABLES RELATIVE FREQUENCY Age at ITP diagnosis 43.35 ± 17.69 Time to SLE diagnosis ITP before SLE diagnosis ITP at SLE diagnosis ITP after SLE diagnosis 4.76 ± 99.7011/34 (32.35%)10/34 (29.41%)13/34 (38.24%) ITP Severity Mild Moderate Severe 13/34 (38.24%)8/34 (23.53%)13/34 (38.24%) Hemorragic event during ITP Ecchymosis Intracranial hemorrhage Pulmonar hemorrhage Digestive hemorrhage Gynecological hemorrhage 12/34 (35.30%)5/34 (14.70%)3/34 (8.82%)2/34 (5.88%)1/34 (2.94%)1/34 (2.94%) ITP WHO bleeding scale 2.5 (min= 1; max=4) ITP recurrence 18/34 (52.94%) Number of recurrences 2 (min= 1; max= 6) ITP treatment Corticoids, dose and need of boluses 25/34 (73.59%), 36.94 ±36.07mg and 9/34 (26.47%) Antimalarials 14/34 (41.18%) Mycophenolate 9/34 (26.47%) Rituximab 7/34 (20.58%) Azathioprine 6/34 (17.65%) Methotrexate 2/34 (5.88%) Splenectomy 2/34 (5.88%) Romiplostim 1/34 (2.94%) Eltrombopag 1/34 (2.94%) Leflunomide 1/34 (2.94%) Belimumab 1/34 (2.94%) Summary/Conclusion: Patients with SLE who develop ITP appear to have a different phenotype than those who do not develop it, presenting less arthritis and more hemolytic anemia at the time of diagnosis, in addition to a higher positivity for APS antibodies during the course of the disease. Additionally, having developed ITP was associated with a higher SLICC and with more frequent treatment with mycophenolate and azathioprine, indicating probably a more severe disease, which could require a more strict follow-up of these patients. Keywords: Immune thrombocytopenia (ITP), Autoimmune disease