Nearly four out of five (78 percent) Medicare Advantage (MA) prescription drug plan enrollees didn’t change their plan between 2013 and 2014, which the Kaiser Family Foundation said raises questions about whether seniors have what they need to compare coverage.

The foundation’s survey said about 11 percent of MA enrollees voluntarily switched plans, a share which has remained relatively consistent since 2007. Just 5 percent switched involuntarily because their plan exited the MA market while 2 percent chose to switch to traditional Medicare. Some 3 percent of enrollees died before the start of the 2014 calendar year.

“Enrollees may be sticking with their plan for a number of reasons,” wrote researchers Gretchen Jacobson, Tricia Neuman and Anthony Damico. “They may be satisfied with their coverage. They may decide they would rather pay a bit more in premiums to avoid the hassle and time involved with making a change, particularly because most face a premium increase of less than $10 on average, in 2014.

"In focus groups, seniors have said that they appreciate the opportunity to change plans but often feel that the differences across plans are not important enough to warrant the time and effort it takes to compare and change plans. Some enrollees may place a higher value on other factors, such as having access to specific doctors or the comfort of sticking with a plan that is familiar.”

MA enrollees switched plans far less frequently than customers on the Affordable Care Act (ACA) exchanges, even when involuntary and voluntary switchers are combined (17 percent in MA vs. 43 percent in ACA exchanges between 2015 and 2016).

Not surprisingly, cost seemed to be the determining factor for the customers who decided to switch plans. The higher the premium increase, the more likely enrollees were to change their source of coverage, with 29 percent who were due to pay an additional $40 or more in premiums switching plans. Notably, 9 percent of enrollees whose premiums would be reduced also changed their coverage, about the same rate as customers facing premiums increases under $20.  

Those who did switch saw some savings. Enrolled who changed coverage saved an average of $15.87 per month on their premiums and lowered out-of-pocket spending limit by an average of $401.  

Enrollees were also more likely to switch from plans with lower star quality ratings, with 14 percent of customers in plans with 2 to 2.5 stars changing coverage. Only 3 percent of enrollees in 5-star plans switched.