Background: the UK Small Aneurysm Trial was established to test the benefit
of prophylactic elective surgery for small abdominal aortic aneurysms (4.0
-5.5 cm in diameter) and identify prognostic risk factors, including smokin
Patients, methods and outcomes: one thousand and ninety patients (902 men a
nd 188 women, mean age 69.3 years) were randomised to either early elective
surgery or ultrasonography surveillance until the aneurysm diameter exceed
ed 5.5 cm, mean follow-up was 4.6 years. Baseline assessments included lung
function tests and continue (a smoking marker). The principal outcome meas
ures were all-cause mortality and aneurysm rupture.
Results: during the course of the trial, aneurysm rupture was diagnosed in
25 patients and 309 patients died. Whereas self-reported smoking status was
not significantly associated with survival, patients without any trace of
plasma cotinine had a significantly improved long-term (6-year) survival, p
= 0.02. Current smokers had a lower FEV1 than post- and never-smokers. FEV
1 was the most powerful predictor of long-term (6-year) survival, the crude
death rates per 100 person-years were 9.1, 6.9 and 4.6 for those with FEV1
<1.91, 1.9-2.51 and >2.51 respectively, p = 0.001. Moreover, the rupture r
ate was 1.9% per year for patients positive for plasma cotinine compared wi
th 0.5% in those without trace of plasma cotinine, p = 0.004.
Conclusions: self-reported smoking status underestimates the effect of cont
inued smoking on the prognosis of patients with small abdominal aortic aneu
rysm. Patients with high plasma cotinine concentrations (smokers) have an i
ncreased risk of aneurysm rupture and poorer long-term survival.