Millions of Americans enrolled in Medicare could face higher monthly costs for prescription drug coverage in 2027, according to a new analysis by health policy research group KFF.

Roughly 4 million Medicare beneficiaries who currently pay no monthly premiums for their prescription drug plans could face new costs next year, potentially paying up to $50 a month, according to the analysis.

The changes could affect beneficiaries who keep their current plans as well as those who switch to new coverage.