Long-term outcome of patients with aortic aneurysms taking low-dose aspirin: A population-based cohort study

Background: Limited studies evaluated the association between lowdose aspirin use and abdominal aortic aneurysm (AAA), thoracoabdominal aortic aneurysm (TAAA), and thoracic aortic aneurysm (TAA) treatment. We conducted this study to investigative the association of low-dose aspirin in terms of preventing death and exacerbation of different aortic aneurysms. Methods: This retrospective study identified aortic aneurysm cases between 1999 and 2006 from the National Health Insurance Research Database and used time-dependent methods to determine whether the use of low-dose aspirin reduced the risk of outcomes. Primary outcomes, including a composite outcome of death, aortic dissection, a rupture event, an unruptured event, or surgical repair, and secondary outcomes, the composite end point of death and readmission for aortic aneurysm events, were estimated separately. Results: Two hundred eighty-seven cases were identified. The hazard ratio for the primary outcome in patients taking low-dose aspirin in AAA/TAAA patients at each 90-day interval based on the time-dependent analysis was 1.000 (95% confidence interval [CI], 0.994-1.005), and in TAA patients 1.010 (95% CI, 0.994-1.026) compared with those with no exposure. In terms of the secondary outcomes, the hazard ratio for all-cause mortality was 0.995 (95% CI, 0.988-1.003) for AAA/TAAA patients and 1.008 (95% CI, 0.991-1.026) for TAA patients. Conclusions: From a national population database, we did not find an association between low-dose aspirin exposure and mortality or exacerbation in different aortic aneurysms by using time-dependent analysis. However, adjustments for aneurysms size and smoking status could not be made, which may limit the validity of the study.