Immune thrombocytopenia and risk of stroke: Evidence from a nationwide population-based cohort study

Background: Research investigating differences in the overall stroke risk between individuals with and without immune thrombocytopenia (ITP) is lacking. Methods: This real-world study used the National Health Insurance Research Database (NHIRD). Risk of stroke was compared between 13,085 individuals with ITP enrolled between 1 January 2000 and 31 December 2015 and a control cohort of 52,340 individuals without ITP (1:4 ratio propensity score–matched by age, sex, index year, relevant comorbidities, and medications). Sub-distribution hazards models were used to estimate adjusted sub-distribution hazard ratio (SHR) and 95% confidence intervals (CIs), with the non-ITP group as the control group. Results: Of the 65,425 participants, 13,085 had ITP, 63.3% were women, and the mean age was 52.59 years. The risk of both ischemic and hemorrhagic stroke was 1.14 times (adjusted SHR 1.14, 95% CI, 1.07–1.22) and 1.93 times (adjusted SHR 1.93, 95% CI, 1.70–2.20) higher in the ITP group than in controls. Patients with ITP in the 20- to 29-year subgroup had a higher risk of new-onset stroke (adjusted SHR, 4.06 (95% CI, 2.72–6.07), p value for interaction Conclusions: ITP is associated with increased risk of both ischemic and hemorrhagic stroke.