A Kaiser Family Foundation study released in August said that in 2007 about 3.4 million Americans enrolled in a Medicare Part D drug plan reached the doughnut hole.  The 3.4 represents 26% of the Medicare Part D enrollees in 2007.  Also, 22% of Medicare Part D enrollees stayed in the doughnut hole for the remaining part of the year while the remaining 4% reached the catastrophic level.  Many seniors combine Medicare Part A and Part B with Medicare supplement coverage for their health insurance and find the addition of a Part D plan very beneficial.  Medicare Part A and B combined with a Medicare supplement gives great flexibility in doctor and hospital selection.  Buying a Part D plan rather than a Medicare Advantage Plan with Part D built in gives the consumer the ability to choose a Part D plan that best fits their RX needs.