In the Medicare population, 65% of patients have two or more chronic illnesses.

The Medicare population differs in significant ways from the general population.

The problem could be exaggerated among the Medicare population, which has low levels of health literacy.

So the amount Congress envisions, $300 billion, would cover about one-fourth of the total anticipated drug spending for the Medicare population.

More than 7 million people now subscribe to such plans, out of a total Medicare population of 42.5 million.

This, despite promised safeguards, would risk inviting plans to pick off healthy applicants in the Medicare population.

The surveys use the Medicare population, which includes about 99 percent of all Americans, regardless of their income levels, who are 65 and older.

Such companies - the card sponsors, known as pharmacy benefit managers - see the Medicare population as an attractive market.

Industry shake-outs will probably continue as more of the Medicare population moves into managed care.

They account for 71 percent of the 85-and-over Medicare population.