Parameter Estimates

The procedure uses the last category of each factor as the reference category; the effect of other categories is relative to the reference category. Note that while the estimate is useful for statistical testing, the exponentiated estimate, Exp(B), is more easily interpreted as the predicted change in the hazard relative to the reference category.

The value of Exp(B) for [mi=0] means that the hazard of death for a patient with no prior myocardial infarctions (mi) is 0.002 times that of a patient with three prior mi's.
The confidence intervals for [mi=0] and [mi=1] do not overlap with the interval for [mi=2], and none of them include 0. Therefore, it appears that the hazard for patients with one or no prior mi's is distinguishable from the hazard for patients with two prior mi's, which in turn is distinguishable from the hazard for patients with three prior mi's.

Similar relationships hold for the levels of is and hs, where increasing the number of prior incidents increases the hazard of death.