There is currently no thrombosis registry in the Kingdom of Saudi Arabia, and although the exact prevalence of deep vein thrombosis (DVT) is unknown, it is estimated that 25,000 people suffer from thrombosis. It is well established that thrombophilia is a predisposition to develop venous thromboembolism (VTE) due to an underlying hypercoagulable state caused by inherited or acquired disorders of coagulation or fibrinolysis. Inherited disorders include deficiencies of natural anticoagulants such as antithrombin, protein C, protein S, elevated levels of coagulation factors (especially factor VIII), and prothrombotic polymorphisms in the genes encoding factor V (i.e., factor V Leiden) and prothrombin. Acquired conditions mainly include antiphospholipid antibody syndrome, malignancies, acquired increases in coagulation factors or acquired decreases in natural inhibitors, and hyperhomocysteinemia.

Despite the growing evidence of thrombophilia in the Saudi population across its regions, there have been no studies on thrombotic events in the Eastern Province of Saudi Arabia, the largest province by area and the most obese region (29.4%), followed by Riyadh (26.9%), while the lowest was Baha (14.3%). This study became the first that aimed to investigate the prevalence of VTE in a hematology clinic in the Eastern Province of Saudi Arabia and compare them with national data. The study was conducted at a tertiary care hospital of King Fahd Military Medical Complex (KFMMC) among n = 170 patients seen in the outpatient clinic between January 2015 and May 2023 who were diagnosed with arterial or venous thrombosis, or both.

It was found that with a mean population age of 42.21 (± 13.022), the prevalence of VTE was 3.16%. Since females constituted 70% of the sample, most cases of VTE were in females, which is consistent with some regional studies within Saudi Arabia. Thus, as shown by the studies from Madinah and the Central Province of Saudi Arabia, the female to male ratio was 2:1. On the other hand, in the Southern Province and Jeddah (Western Province) of Saudi Arabia, the ratio was 1:1. Moreover, the results of the current study are inconsistent with global evidence. Accordingly, it would be erroneous to conclude that females are more likely to develop VTE than males, but it is reasonable to further study this relationship in the future to allow emerging patterns.

The smoking rate (12.9%) in this cohort was high compared to other comparable national data. Given the differences in genetic and ethnic distribution, compared to conflicting data from domestic and international sources, this suggests that active smoking is a possible risk factor for VTE in the Eastern Province of Saudi Arabia.

Obesity-related chronic inflammation and decreased fibrinolysis appear to be two major mechanisms of thrombus formation in obesity. In this study, of n=170 patients, 80.5% were overweight or obese, which confirms national data indicating a high prevalence of obesity and overweight as risk factors for VTE. Moreover, this study showed a significantly higher rate compared to other regional studies in Saudi Arabia.

Further findings showed that the most common causes were rheumatological and autoimmune diseases (39.4%), pregnancy (13.5%), prolonged immobilization (12.4%), positive family history of thrombosis (13%), and oral contraceptives or hormonal therapy (8.8%). These figures were significantly higher compared to regional studies in Saudi Arabia. On the other hand, cancer was more common in Medina, Jeddah, and the Southern Province compared to the Eastern Province, while in the Central Province there was no evidence that cancer was a cause of thrombosis. However, longer hospital stay and VTE as postoperative complications were significantly more common in the Central and Southern Provinces compared to the Eastern Province. Further comparative studies in this area are needed to examine the difference in the incidence of postoperative VTE between the Eastern Province and the Central and Southern Provinces. This may indicate that the postoperative approach and the incidence of in-hospital VTE are lower than other regions, with stricter adherence to preventive measures to prevent postoperative VTE.

The most common comorbidities were cardiac disease, chronic kidney disease (CKD), hypertension (HTN), and type 2 diabetes mellitus, which is consistent with earlier studies in Saudi Arabia. However, compared with the data from Madinah, the data from this study showed a significantly higher rate of comorbidities. Regarding recurrent thrombosis, the results of this study conducted in the Eastern Province showed significantly higher rates compared with other regions of Saudi Arabia. It is important to emphasize that earlier studies in Saudi Arabia did not provide any information on dyslipidemia and VTE to compare with the data from the current study. However, based on existing evidence and current research, lifestyle changes and control of blood glucose, blood pressure, cholesterol, triglycerides, and weight loss may reduce the risk of VTE.

Since there are no recent national or global rates for VTE, determining accurate national data is a matter of further multicenter studies across the Kingdom of Saudi Arabia to substantiate the findings of the current study. In addition, additional improvement efforts and a strategic treatment approach are needed to reduce the factors contributing to VTE in the Eastern Province. Developing an awareness program and supporting lifestyle changes are a critical first step to informing people about VTE and how to reduce its risk.