This study exclusively addressed non-cardiogenic venous thrombosis; the implications for AF-related thromboembolism warrant separate investigation. The annual increase in VTE prevalence observed between January 1, 2018, and December 31, 2023, aligns with the rising burden of altitude-related comorbidities in the region, such as hypertension (33.12%) and low haemoglobin levels (30.24%), which were significantly associated with VTE risk in our cohort.

The incidences of DVT and PE significantly increase with age (Patel et al., 2020), particularly after the age of 55. By the age of 80, the incidence rates reach approximately 1 in 100 per year, which is approximately 1000-fold higher than for those aged 45 years or younger. Furthermore, the rates of PE rapidly increase compared to those of DVT in older adult populations (Silverstein et al., 2007). Environmental factors can also lead to heightened DVT and PE incidences in younger demographics. The altered daily activities in HA regions, including occupational and recreational pursuits, may affect blood flow and thrombosis risk. Moreover, the scarcity of medical resources in these areas may impede early diagnosis and treatment of DVT and PE, possibly resulting in a higher incidence among younger individuals.

A notable observation in the present study was that approximately 30.70% of patients with thrombosis had haemoglobin levels below the normal range, suggesting a prevalent incidence of anaemia. This contradicts the common perception that HAs lead to polycythaemia (Gatterer et al., 2024). Approximately half of the patients (49.37%) exhibited reduced eGFR (estimated glomerular filtration rate) below the normal range, suggesting potential renal insufficiency. This finding aligns with previous reports of altered renal haemodynamics in high-altitude populations (Hurtado- Arestegui, A. et al., 2018). Moreover, a significant number of the samples (78.45%) were outside the reference range for homocysteine, with a particularly high percentage (47.51%) falling below the lower limit, indicating potential metabolic anomalies associated with an increased risk of cardiovascular diseases.

The co-occurrence of hypertension was the most prevalent among patients with VTE (33.12 %). Although hypertension is a recognized risk factor for arterial thrombosis (Miraclin et al., 2024), its direct role in VTE risk remains unclear. However, patients with hypertension should be carefully monitored owing to their elevated risk for cardiovascular complications. Following AMI or stroke, immobility, particularly paralysis, inflammation, and hypercoagulability, can predispose patients to VTE (Anderson et al., 2003; Gregson et al., 2019).

In the management of VTE, anticoagulant therapies are fundamental to preventing the formation or enlargement of blood clots. This highlights significant differences in the types and conditions of medications prescribed at discharge, depending on the different discharge diagnoses (Cohen et al., 2020). Rivaroxaban plays a pivotal role in the coagulation cascade. Its benefits include predictable pharmacokinetic profiles, elimination of routine monitoring, and minimal dietary interactions. Rivaroxaban dosing is contingent upon clinical indications and treatment phase, necessitating adjustments for renal function, potential drug interactions, and bleeding risks. For example, a regimen of 15 mg once daily may be appropriate for patients with moderate renal dysfunction after the initial treatment phase. For initial DVT and PE management, 15 mg twice daily with meals is recommended for the first 21 days, followed by a maintenance dose of 20 mg once daily (Gao et al., 2021). In our study, patients administered rivaroxaban typically received conventional treatment regimens, with only one case involving an outpatient medication regimen of rivaroxaban at a dosage of 30 mg once daily and another involving a two-year-old administered a dose of 2 mg once daily for venous sinus thrombosis.

The duration of anticoagulation therapy ranges from a minimum of three months to potentially lifelong treatment, contingent on reversible risk factors, recurrence risk, and the patient’s bleeding risk. One of the key challenges associated with anticoagulant administration in populations at HAs is that standard anticoagulants, such as warfarin, heparin, or direct oral anticoagulant drugs, may display different pharmacokinetics or pharmacodynamics due to the altered vascular environment and reduced oxygen levels. Additionally, given the changes in coagulation function, possibly occurring due to the plateau environment, adjustments in anticoagulant dosing or treatment strategies may be required. These unique environmental factors suggest that standard protocols may not be applicable in HA settings.

However, we acknowledge that the present study has a few limitations. First, relying on data from a single hospital, even one with a significant catchment area, may not fully represent the general population. Second, the lifestyle of Tibetan patients, including dietary habits, physical activity, and cultural practices, could markedly influence the outcomes of anticoagulant therapy. Third, traditional Tibetan medicine, such as herbal treatments or acupuncture, may also interact with conventional anticoagulant therapy. Fourth, genetic predispositions influencing clotting mechanisms in the Tibetan population could introduce bias in conclusions regarding anticoagulant effectiveness. Finally, unaccounted factors, such as climate-related stress and social determinants of health (e.g., social support and education level) may have skewed the analysis, thereby limiting the validity of our findings. Therefore, further research addressing these aspects is necessary to validate our findings and define protocols that are safe and effective for patients under similar conditions.

Further statistical analyses, including those using multivariate models, may help elucidate the relative contributions of these factors to the thrombotic risk in this patient population. Additionally, such analyses could be enhanced by incorporating qualitative data on patient history, medication regimens, and other clinical variables to gain a comprehensive understanding of the pathogenic mechanisms underlying the occurrence of VTE.

Real-world studies provide valuable insights into the impact of HA environments on the prevalence of VTE. These findings can inform the refinement of VTE risk assessment models, incorporating high-altitude environments as a distinct consideration in clinical guidelines. Based on such data, guidelines could recommend deploying more sensitive screening tools or adopting proactive imaging strategies in high-altitude regions, particularly for high-risk groups such as individuals with prolonged immobility, a history of thrombosis, or those recovering from surgery. Furthermore, these studies can help identify populations uniquely vulnerable to high-altitude conditions, such as individuals with polycythaemia, older adults, and postoperative patients, allowing for the development of targeted prevention and treatment strategies. VTE research at HAs also has the potential to garner attention to the health challenges posed by unique geographic conditions globally, paving the way for the establishment of globally standardized guidelines to support patients in similar environments, such as those characterized by hypoxia or extreme climates.