Introduction: Critically ill patients with COVID 19 exhibit a pronounced hypercoagulable state, predisposing them to deep vein thrombosis during ICU admission. Inflammation driven endothelial dysfunction, hypoxia, and immobilization contribute to this elevated risk. Determining the true prevalence of DVT in this population is essential for optimizing thromboprophylaxis strategies and improving clinical outcomes.

Material and methods: This retrospective observational study evaluated critically ill patients with concurrent COVID 19 and active malignancy admitted to a tertiary ICU. Clinical records, laboratory parameters, and imaging confirmed thrombotic events were systematically analyzed. Multivariable logistic regression was applied to identify independent risk factors for vascular thrombosis, providing clinically relevant insights for risk stratification and management in this high risk population.

Results: Thrombotic complications occurred in 28.3% of critically ill ICU patients with concurrent COVID 19 and active malignancy, while 71.7% remained free of thrombosis (P < 0.001). Among affected patients, venous thromboembolism predominated, with lower extremity deep vein thrombosis and pulmonary embolism being the most frequent manifestations, whereas arterial, cerebral, and coronary events were uncommon.

Conclusion: In conclusion, thrombotic complications remain a common and clinically significant problem among ICU patients with concurrent COVID 19 and active malignancy. Venous thromboembolism predominates, and its occurrence is associated with older age, higher BMI, specific cancer types, greater comorbidity burden, prolonged ICU stay, increased need for mechanical ventilation, and higher mortality.