Dual-eligible beneficiaries were entitled to millions of dollars in retroactive Medicare Part D payments in 2006. But many may not have collected because the government did not notify them of this right until this year, according to a new government study released Tuesday. About 25% of dual eligibles live in long-term care facilities, the report notes.

When Medicare recipients become eligible for Medicaid, their Part D status extends retroactively to the date their Medicaid status became effective. In 2006, Medicare paid prescription drug plans millions of dollars for this retroactive coverage, according to the Government Accountability Office report. However, the Centers for Medicare & Medicaid Services only told dual eligibles of their right to claim this money in March of 2007.

“Given their vulnerability, it is unlikely that these beneficiaries would have sought reimbursement or retained proof of their drug purchases if they were not informed of their right to do so,” the GAO report said. CMS acting Administrator Leslie Norwalk said she objected to the negative tone of the report’s findings.