Can COVID-19 Increase Platelet in Adult Immune Thrombocytopenia During the TPO-RA Administration? A Real-World Observational Study

Introduction: COVID-19 infection has brought new challenges to the treatment of adult patients with immune thrombocytopenia (ITP). In adult ITP patients, there have been no relevant reports exploring the incidence, clinical characteristics, and risk factors of platelet elevation after COVID-19 infection. Materials and Methods: A total of 66 patients with previously diagnosed ITP from December 2022 to February 2023 in a single-center were collected and analyzed for this real-world clinical retrospective observational study. Results: In the platelet count increased group (n = 19), 13 patients (68.4%) were using thrombopoietin receptor agonists (TPO-RA) treatment at the time of COVID-19 infection; the median platelet count was 52 (2– 207) × 10 9 /L at the last visit before infection and 108 (19– 453) × 10 9 /L at the first visit after infection. In the platelet count stable group (n = 19) and platelet count decreased group (n = 28), 9 (47.4%) and 8 (28.6%) patients were using TPO-RA at the time of infection, respectively. ITP patients treated with TPO-RA had a significantly higher risk of increased platelet count than those not treated with TPO-RA at the time of infection (platelet count increased group vs platelet count decreased group: OR: 5.745, p = 0.009; platelet count increased group vs the non-increased group: OR: 3.616, p = 0.031). In the platelet count increased group, the median platelet count at 6 months post-infection was 67 (14– 235) × 10 9 /L, which was significantly higher than the platelet level at the last visit before infection (p = 0.040). Conclusion: This study showed that some adult ITP patients had an increase in platelet count after COVID-19 infection, and this phenomenon was strongly associated with the use of TPO-RA at the time of infection. Although no thrombotic events were observed in this study, it reminds clinicians that they should be alert to the possibility of thrombotic events in the long-term management of adult ITP patients during the COVID-19 pandemic. Keywords: immune thrombocytopenia, thrombopoietin receptor agonists, COVID-19, thrombosis