Aspirin Is Associated With Reduced Rates of Venous Thromboembolism in Older Patients With Cancer.

Background: Older patients with cancer are at high risk of developing venous thromboembolism (VTE) and bleeding. Aspirin may decrease VTE in the general population without significant bleeding. Here, we examined whether aspirin is associated with reduced rates of VTE in older patients with cancer. Methods and Results: Using the National Inpatient Sample 2016, we retrospectively identified a cohort of patients with cancer >= 65 years old who received aspirin and a similar cohort who did not receive aspirin (n = 31 654, each). The cohorts were matched for age, sex, race, patient demographics, insurance, hospital demographics, and 9 comorbidities (smoking, obesity, hypertension, hyperlipidemia, diabetes, chronic kidney disease, chronic obstructive pulmonary disease, congestive heart failure, and history of deep venous thrombosis [DVT]/pulmonary embolism [PE]). Primary outcomes were discharge diagnosis of acute PE or acute DVT. Secondary outcomes were inhospital mortality, bleeding, length of hospital stay (LOS), and total hospitalization cost. The aspirin group, compared with the nonaspirin group, had a significantly lower incidence of acute PE (matched, 2.1% vs 2.6%, P < .001), acute DVT (matched, 2.3% vs 3.2%, P < .001), and inhospital mortality (matched 4.0% vs 6.5%, P < .001); shorter LOS (matched, 5.29 +/- 5.01 vs 6.20 +/- 6.56 days, P < .001); and lower total costs (matched, US$14 700 +/- 15 031 vs US$16 363 +/- 20 219, P < .001). The primary and secondary outcomes were similar before and after propensity matching. We found no increase in bleeding in the aspirin group compared to the nonaspirin group: gastrointestinal bleeding (matched, 3.8% vs 4.0%, P= .168), hematuria (matched, 3.5% vs 3.7%, P = .102), hemoptysis (matched, 0.9% vs 0.9%, P = .532), and hemorrhagic stroke (matched, 0.8% vs 0.8%, P = .443). In subgroup analyses, aspirin was associated with decreased inhospital mortality, mostly in patients with lung, colon, pancreatic, prostate, breast cancer, lymphoma, and leukemia. Conclusions: Among older patients with cancer, aspirin was associated with lower VTE incidence and overall inhospital mortality without significantly increased bleeding.