Background: Ovarian Cancer is one of the most common gynecological cancers. It has 5-year relative survival of 50.8 %. Around 12700 people die from this cancer each year, and it ranks fifth in cancer death among women. Studies have shown a strong association of ovarian cancer with venous thromboembolism (VTE) which includes deep venous thrombosis (DVT) and Pulmonary Embolism (PE). However, data surrounding outcomes associated with VTE in this population is limited. We aim to estimate the effect of VTE on mortality and healthcare utilization in this population. Methods: We queried the National Inpatient Sample (NIS) 2018-2020 to collect data for all adult hospitalizations >18 years with a diagnosis of ovarian cancer using appropriate ICD 10 codes. These hospitalizations were further classified into hospitalizations with and without DVT and PE. Multivariate regression analysis was performed to study the impact of DVT/PE taking mortality as the primary outcome and total cost and length of hospital stay (LOS) as secondary outcomes in the subpopulation of ovarian cancer hospitalizations. Results: There were a total of 298085 adult hospitalizations with a diagnosis of ovarian cancer with a mean age of 63 years. Among hospitalizations with ovarian cancer, acute DVT was found in 2.75% and acute PE was present in 4.5 %. In these hospitalizations, in-patient mortality was 9.3% in those with either DVT or PE. Multivariate regression analysis revealed that among adults, hospitalizations with ovarian cancer had higher odds of Acute DVT [OR 3.5, P<0.01] and Acute PE [OR 3.76, P<0.01] than those without. The odds of all-cause mortality from VTE [OR 2.18, P<0.01] were significantly higher in patients with ovarian cancer than those without. The total cost of hospital stay was 26211 $ ($22183 - $30238, p<0.01) higher and LOS was 1.67 times higher (1.2 - 2.32; P<0.01) when patients with ovarian cancer developed VTE (Table). Conclusions: Our study concludes that ovarian cancer patients who develop VTE tend to have worse outcomes in terms of mortality. Length of hospital stay and total hospital charge are also increased in patients developing VTE, thereby increasing healthcare utilization. This highlights the importance of having larger-scale studies in the future to assess outcomes in ovarian cancer patients with VTE and the need to formulate risk assessment models for the role of primary thromboprophylaxis. Adjusted analysis showing odds ratio of mortality, total hospital charge and LOS in ovarian cancer hospitalizations.

*Adjusted for family history of ovarian cancer, oral contraceptive use, breast cancer, obesity, smoking, alcohol, hypertension, diabetes, and dyslipidemia.