This distinction proved to be significant
(p = 0.013), so that it is estimated that there is a
2.3 times higher risk of postoperative bleeding in the
group of patients above 35 years of age than for those
aged up to and including 35. The 95% CI for this socalled
odds ratio is 1.2–4.7. On the basis of the
presupposition that age dependence is especially connected
with the à chaud operations, this hypothesis
was investigated more closely using a model that permitted
different age dependence for the two groups of
operation, à chaud and à froid: P-OB ~ 1+(age > 35,
diag=à froid) + (age > 35,diag=à chaud).