title: High-risk and low-risk screening for abdominal aortic aneurysm both reduce aneurysm-related mortality. A stratified analysis from a single-centre randomised screening trial.
abstract: BACKGROUND
  Cardiovascular diseases and chronic obstructive pulmonary disease (COPD) are both associated with abdominal aortic aneurysms (AAA). The aim of this study was therefore to analyse whether screening for AAA could be restricted to men with such diseases (high risk group).
  
  
  METHODS
  Before the date of randomisation of a population screening trial of 12,639 64-73-year-old males, all discharge diagnoses from the National Patient Registry concerning AAA-related diseases were merged with the screening results on attendance, AAA prevalence, and AAA-related mortality and overall mortality. Differences in proportions were compared by Chi square tests and differences in mortality by Cox regression analyses.
  
  
  RESULTS
  The attendance rate was 78.8% and 6.7% had an AAA in the high risk group compared to 75.8% attendance (P<0.001) and 2.9% (P<0.001) in the remaining population. Cumulatively, screening of only high risk men with would have required 72.9% (95% C.I.: 72.3-74.5%) fewer screening invitations, would have discovered 46.1% (95% C.I.: 38.9-53.4%) of the AAA cases diagnosed and prevented 46.7% (95% C.I.: 28.3-65.7%) of the AAA-related deaths. However, screening decreased AAA-related mortality both among men with and without known COPD or cardiovascular diseases: mortality ratio: 0.22 (95% C.I.: 0.08-0.65), P=0.006, and 0.24 (95% C.I: 0.09-0.63, P=0.004, respectively.
  
  
  CONCLUSIONS
  High-risk population screening would prevent less than half of AAA-related deaths. Therefore, restricting screening to such high-risk groups does not seem justified, but cost effectiveness analyses are needed to reach a firm conclusion.
authors.affiliation: Vascular Research Unit, Department of Vascular Surgery, Viborg Hospital, Viborg, Denmark. jes.s.lindholt@sygehusviborg.dk
authors.forename: J S
authors.initials: JS
authors.lastname: Lindholt
authors.forename: S
authors.initials: S
authors.lastname: Juul
authors.forename: E W
authors.initials: EW
authors.lastname: Henneberg
mesh_terms: D000368:Aged; D017544:Aortic Aneurysm, Abdominal / Q000150:complications / Q000401:mortality*; D016009:Chi-Square Distribution; D003718:Denmark / Q000453:epidemiology; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods*; D015995:Prevalence; D016016:Proportional Hazards Models; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000453:epidemiology; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D015996:Survival Rate / Q000639:trends; D013997:Time Factors