Analysis: Premiums rose sharply in Medicare drug plans

"Seniors need to carefully assess their options going into this open season to ensure that they have a plan that meets their needs," said Avalere senior vice president Bonnie Washington in a statement.

The top 10 PDP with the highest premium increase was the Humana Walmart Preferred RX Plan, which saw a 23 percent rise to an average premium of $18.50. More than 1.5 million seniors are in enrolled in that plan, the report stated.

The second-highest increase among the top 10 plans hit First Health Part D Value Plus, rising 17 percent to $29.75. This change means low-income subsidy beneficiaries in 10 U.S. religions will no longer be eligible in 2013.

Overall, PDP premiums rose an average of 6 percent between 2012 and 2013, according to Avalere.