Immune thrombocytopenia (ITP) is an acquired bleeding disorder mediated by immune-related platelet destruction and impaired platelet production. Immune thrombocytopenia may increase the risk of cerebral infarction and represents a relatively uncommon etiology of acute ischemic stroke. This disease is associated with high disability and mortality rates, poses significant therapeutic challenges, and constitutes a serious threat to human health. Therefore, research on the diagnosis, treatment, and prognosis of ITP combined with acute ischemic stroke is of great significance for improving patients' quality of life and survival outcomes. However, most current hematologic cohort studies are based on single-center or limited multicenter sample sizes, lacking comprehensive and large-scale prospective cohort studies. Our center plans to conduct a large-sample, combined retrospective and prospective longitudinal cohort study. This study will register patients' basic information and diagnosis, follow up with patients through questionnaires, telephone calls, video consultations, online platforms, and in-person visits to record treatment and comorbidity data, collect prognostic information, and retrieve hospitalization and outpatient costs through medical record systems. The study aims to provide comprehensive data on the incidence, treatment, prognosis, and healthcare costs of ITP patients with acute ischemic stroke in China.

Immune thrombocytopenia (ITP) is an immune-mediated acquired bleeding disorder characterized by thrombocytopenia, with normal or increased megakaryocyte counts in the bone marrow but impaired maturation. The estimated incidence in the general population is approximately 2 to 5 cases per 100,000 individuals. The primary clinical manifestation of ITP is bleeding, ranging from mild skin/mucosal bleeding to life-threatening organ hemorrhage. However, some patients also face an increased risk of thrombosis/embolism. Embolic events in critical organs such as the heart and brain can severely impact patients' quality of life and lead to life-threatening complications.

In China, there are approximately 3.94 million new stroke cases annually, of which acute ischemic stroke (AIS) is the most common type, accounting for 69.6% to 72.8% of all new stroke cases. From an epidemiological perspective, AIS is a globally prevalent disease that significantly affects the quality of life and physical health across populations.

Research indicates that immune thrombocytopenia increases the risk of cerebral infarction and represents a relatively uncommon but important etiological factor for acute ischemic stroke. Currently, most cohort studies on ITP in China are either single-center studies or limited multicenter studies with small sample sizes, resulting in insufficient data and a lack of large-scale, longitudinal prospective cohort studies.

This study is a multicenter, retrospective and prospective longitudinal observational study that will enroll patients diagnosed with ITP and concurrent acute ischemic stroke. It will collect baseline patient information and diagnostic data, conduct regular prospective follow-ups via questionnaires, telephone interviews, video consultations, online platforms, and in-person visits, and record treatment regimens, comorbidities, and prognostic outcomes. Additionally, hospitalization and outpatient costs will be extracted from medical records. The study aims to provide comprehensive data on the epidemiology, treatment patterns, clinical outcomes, and healthcare costs of ITP patients with AIS in China, ultimately supporting the development of novel diagnostic and therapeutic strategies and improving long-term bleeding-free survival rates.

Inclusion Criteria:

1. Diagnosed with immune thrombocytopenia, and subsequently identified patients with acute ischemic stroke.
2. Since January 1, 2005, patients who received treatment at Peking University People's Hospital.

Exclusion Criteria:

1. For any reason, such as the occurrence of severe mental disorders, the follow-up information may be unavailable;
2. Patients deemed unsuitable for the study by the researchers.

Patients with confirmed immune thrombocytopenia (ITP) combined with acute ischemic stroke（AIS)

Diagnostic Criteria for ITP:

1. Sustained platelet count <100×10⁹/L
2. Normal or increased megakaryocyte count in bone marrow with maturation defects
3. Exclusion of other potential causes of thrombocytopenia including: pseudothrombocytopenia, drug-induced thrombocytopenia, viral infections, helicobacter pylori infection, hematologic disorders, autoimmune diseases, hypersplenism, malignancies

Diagnostic Criteria for AIS:

1. Acute onset;
2. Focal neurological deficits (weakness or numbness of one side of the face or limb, language disorders, etc.), with a few cases presenting with comprehensive neurological deficits;
3. The presence of a responsible lesion on imaging or the symptoms/signs persisting for more than 24 hours;
4. Elimination of non-vascular causes;
5. Brain CT/MRI ruling out cerebral hemorrhage.