Thanks Bear for what seems to be a credible hypothesis for the difference in reponse between the two LDL groups!  I would just take a little issue with the following suggestion:

"Also, if you look at slide 32, you can see that the below median LDL-C placebo group had a higher MACE risk than the above median LDL-C placebo group, consistent with my suggestion above that the below median LDL-C group may be enriched in those with more atherogenic (and less cholesterol rich) LDL particles."

On slide 32, events are counted multiple times in various categories and it is hard to sort actual event numbers.  From slide 19:

The placebo MACE rate for the below median LDL group was 78/597 or 13.1% and for the above median LDL group was 71/606 or 11.7%.  So, technically you are right (13.1 is higher than 11.7) but I don't think the difference is signficant.  I would say the placebo numbers indicated that the two groups were at equal risk.  One reason I choose to quibble on this point is so that I can correct my own previous mis-statement that the low LDL group was at lower risk.  This was based on combined placebo and treatment MACE rates and is clearly incorrect. 

In contrast to the lack of difference in MACE rates between the two placebo groups, the difference in MACE rates between the apabetalone groups is large.  For the below median LDL group the apabetalone MACE was 48/595 (8.1%), a 38% RRR over the control value of 13.1.  For the above median LDL group that apabetalone MACE was 77/618 (12.5%), a nonsignficant increase in risk over the 11.7% in the control group for a zero% RRR.

Bear's hypothesis may explain the difference in response to apabetalone between the two LDL groups.

Jupe