Bear,

I am not sure but I think the P=0.032 is the signficance for the comparison of the two HRs.  An interaction effect is actually what you are looking for when you expect one subgroup to respond differently to the drug than another subgroup.

Besides, if it was a comparsion of drug with placebo, there would be two comparisons (and two P values given), one for each subgroup (greater than and less than 60).

Jupe