Purpose <p>Immune thrombocytopenia (ITP) is an autoimmune disorder characterized by low platelet counts due to the destruction of platelets by autoantibodies. The presence of hepatitis&#xa0;B core antibodies (anti-HBc) is a&#xa0;marker of previous or occult hepatitis&#xa0;B virus (HBV) infection, which may influence the clinical course and treatment outcomes in ITP patients.</p> Methods <p>This retrospective study investigated the impact of anti-HBc positivity on the clinical outcomes and response to treatment in ITP patients. A&#xa0;total of 116 patients with ITP were divided into 2 groups: those who were anti-HBc positive (<i>n</i> = 31) and those who were anti-HBc negative (<i>n</i> = 85). Clinical data, including platelet counts at diagnosis and during follow-up, response to corticosteroid treatment and remission rates were analyzed.</p> Results <p>The results indicated that anti-HBc positive patients had significantly lower platelet counts at diagnosis (<i>p</i> = 0.009) and a&#xa0;longer hospital stay (<i>p</i> = 0.042). Additionally, these patients demonstrated lower complete response rates to initial corticosteroid treatment at 1&#xa0;month (<i>p</i> = 0.001) and 6&#xa0;months (<i>p</i> = 0.021) compared to anti-HBc negative patients; however, there were no significant differences in overall response or durable response rates between the groups at 12&#xa0;months. The risk of relapse was higher in anti-HBc positive patients (<i>p</i> = 0.041).</p> Conclusion <p>These findings suggest that anti-HBc positivity may be associated with a&#xa0;more severe disease course and reduced treatment efficacy in ITP, highlighting the importance of assessing hepatitis&#xa0;B serological markers when managing ITP patients.</p>