Coinsurance requires patients to pay a certain percentage of the price of the drug out of pocket, as opposed to a flat amount in the form of a copayment. The remaining cost of the drug is covered by the Part D plan.
The percentage of Medicare Part D drugs that require coinsurance has skyrocketed from 35 percent in 2014 up to 58 percent his year, Avalere Health said in its report. Most Part D beneficiaries are senior citizens.
The report also found that 96 percent of all Part D plan customers in 2016 are in plans that impose coinsurance across more than just one tier of drugs covered by the plans. That is up from just 39 percent of all beneficiaries in 2014, when coinsurance was apt to be applied for higher-cost specialty drugs.
"Coinsurance often leads to patients paying more out of pocket compared to fixed dollar amount copayments," Avalere noted in its report.
The research also found that coinsurance is less likely to be used in Medicare Advantage plans, most of which have prescription drug components, along with covering doctor visits and hospital stays for enrollees. Just 26 percent of the drugs in Medicare Advantage plans — which cover almost 14 million people — have a coinsurance requirement for 2016, according to the analysis.