Long-term Outcome of Patients with Aortic Aneurysms Taking Low-dose Aspirin: a Population-based Cohort Study

Background: Limited studies evaluated the association between low-dose 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.