PB1207 - Effect Of Anti-Nuclear Antibody Positivity On Adult Newly Diagnosed Immune Thrombocytopenia Prognosis.

Background: Idiopathic thrombocytopenia (ITP) is an acquired autoimmune disease that may be associated with other autoimmune disorders. Patients with primary ITP are occasionally found to have a positive Antinuclear Antibody (ANA).

Aims: Our objective was to study the effect of positive ANA on ITP clinical course.

Methods: This was a retrospective descriptive study of adult patients with newly diagnosed ITP, treated at Cho Ray Hospital from February 2020 till July 2021. Baseline characteristics regarding age, sex, bleeding grade, hemoglobin level, platelets count at presentation, hospital length of stay, in-hospital amounts of blood products transfused, corticosteroid responsiveness, sustained response (SR) were recorded.

Results: 152 patients fulfilled the inclusion criteria. ANAs were positive in 41 (27%) of the included patients, 3.3% had “uncertain” results with ELISA test.
Patients with positive ANA had higher mean severe bleeding grade according to IWG criteria, and lower hemoglobin level at presentation than patients with negative ANA ( 10.63 g/dL vs 11.83 g/dl) (p < 0.01).
The incidence of overall response (R) and complete response (CR) after 2 weeks of steroids in ANA-positive patients was significantly lower than that in ANA negative patients (overall response: 52.6% vs 70.4%, p< 0.05). This difference between positive and negative ANA patients remained significant after adjusting for sex, C3, C4, antiDsDNA (p < 0.05). Patients with a positive ANA were 2.5 times (95% CI:1,01-6,2) more likely of not achieving a response defined as a platelet count of 30 x 10e9/ml or more after 2 weeks of steroids. However, sustained response (SR) rates in ANA-positive patients at 12 and 18 months were the same as ANA-negative patients (p> 0.05).ANA were also associated with persistent disease (OR: 3.68, 95% CI: 1.14-11.83).

Conclusion(s): Patients with positive ANA had more severe bleeding, more likely to become steroid-resistant, had a higher risk of developing persistent ITP, and presented with lower Hemoglobin level.