The U.S. Department of Health and Human Services Office of the Inspector General (OIG) has released a much-publicized report that shows that from 2011 to 2015, total reimbursement for brand-name drugs in Medicare Part D increased 77 percent even though there was actually a decrease in utilization for these drugs.

Per the report, Part D paid $382 billion for all brand-name drugs for the period mentioned.

The total number of prescriptions for brand-name drugs decreased 17 percent, from 229 million in 2011 to 191 million in 2015. Additionally, the total rebate dollars for all brand-name drugs in Part D more than doubled a 155 percent increase — across the five years, from $9 billion in 2011 to $23 billion in 2015.

"Despite the substantial growth in rebates, the gap between total reimbursement and total rebates increased from 2011 to 2015," the OIG report said. "Therefore, total rebate-adjusted reimbursement under Part D still increased 62 percent, from $49 billion in 2011 to $80 billion in 2015."

The percentage of brand-name drugs for which manufacturers paid rebates also decreased. They paid rebates for 72 percent of brand-name drugs in 2011, but paid rebates for 61 percent of brand-name drugs in 2015. "Part D unit costs for brand-name drugs rose nearly six times faster than inflation from 2011 to 2015."

However, the average unit cost for brand-name drugs with Part D reimbursement in all five years increased 29 percent; nearly six times greater than the 5 percent increase in the consumer price index measure of inflation.

Brand-name benchmark drugs in Part D also increased faster than inflation with the OIG report, noting that it found that while the rate of inflation slowed, the prices actually increased by about 10 percent for brand-name drugs reimbursed by Part D in two consecutive years. Likewise, for almost half of brand-name drugs reviewed, Part D unit costs increased at least 50 percent.

Of the 3,578 brand-name drugs that were reimbursed by Part D, 89 percent had unit cost increases across the five-year span. The average unit cost for these brand-name drugs increased 29 percent, from $115 in 2011 to $148 in 2015.

For nearly half of brand-name drugs reimbursed by Part D from 2011 to 2015 unit costs increased at least 50 percent; Part D spent $12 billion more for these same drugs in 2015 than in 2011.

For 15 percent of drugs reviewed, unit costs were at least six times higher in 2015 than in 2011.

The OIG findings show that "although there were fewer prescriptions for brand-name drugs in 2015 than in 2011, increases in Part D unit costs for brand-name drugs led to greater overall Medicare Part D spending and higher beneficiary out-of-pocket costs for these drugs. Generally, plan sponsors base their pharmacy reimbursement amounts on the prices that manufacturers set for their drugs. Therefore, increasing manufacturer prices for brand-name drugs may result in increasing costs for Medicare and its beneficiaries, especially those beneficiaries who need access to expensive maintenance drugs."

The Medicare Part D Program was established by the Medicare Prescription Drug, Improvement, and Modernization Act of 2003 to provide an optional prescription drug benefit for Medicare beneficiaries beginning Jan. 1, 2006.

Individuals enrolled in Part D can choose to receive benefits through stand-alone prescription drug plans or through Medicare Advantage prescription drug plans that provide integrated medical coverage, including drugs. Part D typically covers outpatient drugs, including cardiovascular, insulin, antibacterial and some vaccines.

The Centers for Medicare & Medicaid Services contracts with private companies, known as plan sponsors, that offer prescription drug plans to their beneficiaries with varying drug coverage and cost-sharing requirements.

Consumers are being hit with the higher costs for drugs as the number of people who paid more than $2,000 in out-of-pocket costs almost doubled during the five-year period.

The OIG report comes as the Trump administration tries to address rising drug prices, which could include transferring some Part B drugs to Part D. Recent analysis found that policy change could mean higher out-of-pocket spending for beneficiaries, though.