Background & Objectives: Venous thromboembolism (VTE) is one of the three causes of mortality made by cardiovascular disease and pulmonary embolism is the most common preventable causes of mortality among hospitalized patients. Considering high prevalence, the importance of etiologic studies of diseases and different previous reports regarding the role of blood groups on occurrence of diseases such as VTE, this study was carried out to determine the blood groups of the hospitalized patients with diagnosis of VTE.

  Methods: This cross-sectional study was carried out on 200 hospitalized patients with the diagnosis of deep vein thrombosis (DVT) and pulmonary embolism (PE) in Imam, Fatemi and Alavi hospitals in Ardebil. The final diagnosis was made by c olour D oppler ultrasound and pulmonary CT angiography and blood groups and risk factors were determined. Results of this study analysed along with the previous epidemiologic reports related with blood groups in Ardebil and Iran population using chi-square and t-test and SPSS software.

  Results: Of 200 patients with VTE, 140 patients were affected with DVT and 60 patients with PE. In this study, 92 patients were males and 108 were females. The mean age of patients was 52 ± 19 years. The most prevalent blood group was type A with a rate of 47.5%. There was no correlation between the diseases namely DVT or PE and blood groups (P=0.55). Frequency of type A ( OR: 2.914) and B ( OR: 1.608) in patients with VTE was more than Ardebil and Iran population but the type O (OR: 0.632) was less than those population. These differences were statistically significant. The frequency of type AB was similar in all groups.

  Conclusion: The Correlation between blood groups and venous thromboembolism, which have been discussed in many studies, have been investigated in Iran and at medical centres of Ardebil University of Medical Science for first time. It seems the type of blood groups (A and B) is effective in frequency of VTE. More studies are needed on the correlation between blood groups and VTE.