Hyperhomocysteinemia-associated Thrombosis in Patients With Pernicious Anemia.

Introduction: Cobalamin deficiency (CD) due to pernicious anemia (PA) leads to hyperhomocystinemia, a risk factor for thrombosis. However, the clinical presentations and outcomes of hyperhomocystinemia-associated thrombosis (HAT) are not fully understood. Methods: We undertook a literature search using PUBMED, SCOPUS and WEB OF SCIENCE databases for the terms "pernicious anemia AND thrombosis", "pernicious anemia AND embolism", "pernicious anemia AND thromboembolism", "autoimmune gastritis AND thrombosis", "autoimmune gastritis AND embolism", "autoimmune gastritis AND thromboembolism" through January 2024 and reviewed the published literature. Our aim was to illustrate the clinical features of PA-related HAT. Results: Of 20 patients, the median age was 54.5 years (60 % males). 35 % of patients were elderly. The median serum homocysteine level was 67.75 umol/L. 35 % of patients developed thromboses at multiple locations while 20 % had thromboses at unusual sites. 45 % of patients had co-existing neuropsychiatric symptoms. 80 % of patients were positive for anti-IF (anti-intrinsic factor) antibodies. All patients received cobalamin replacement and the median duration of antithrombotic therapy was 6.5 months for reported cases. None developed recurrent thromboembolism. Conclusion: This rare condition is associated with high incidence of thromboses at unusual sites, multiple-site thromboses, co-existing neuropsychiatric symptoms, high positivity rate for anti-IF antibodies and low recurrent thrombosis rate.