title: Long-term outcome of patients with aortic aneurysms taking low-dose aspirin: a population-based cohort study.
abstract: 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.
authors.affiliation: School of Pharmacy, Kaohsiung Medical University, Taiwan, Republic of China.
authors.forename: Chung-Yu
authors.initials: CY
authors.lastname: Chen
authors.forename: Jiann-Woei
authors.initials: JW
authors.lastname: Huang
authors.forename: Charles
authors.initials: C
authors.lastname: Tzu-Chi Lee
authors.forename: Wen-Ter
authors.initials: WT
authors.lastname: Lai
authors.forename: Yaw-Bin
authors.initials: YB
authors.lastname: Huang
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001014:Aortic Aneurysm / Q000188:drug therapy / Q000401:mortality; D017544:Aortic Aneurysm, Abdominal / Q000188:drug therapy* / Q000401:mortality*; D017545:Aortic Aneurysm, Thoracic / Q000188:drug therapy* / Q000401:mortality*; D001241:Aspirin / Q000008:administration & dosage*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance / Q000379:methods; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D001241:Aspirin