USA (WOWO) — More than one-third of American adults say uncertainty about prescription drug prices has caused them to delay picking up medication, leave a pharmacy without it or take less than prescribed, according to new research from Model N.

The survey found 35% of U.S. adults reported taking at least one of those steps because of unclear prescription costs. Another 46% said they do not consistently know how much a prescription will cost before arriving at the pharmacy.

The findings come as pharmacy benefit managers, or PBMs, face increased scrutiny over their role in the prescription drug market. PBMs work with health plans to negotiate with drug manufacturers, establish lists of covered medications and negotiate rebates and discounts.

The Model N survey found 76% of respondents either had never heard of PBMs or had heard of them but did not know what they do.

Prescription costs can be especially significant for people who regularly need medications such as insulin. About 7.7 million Americans use insulin, while recent American Diabetes Association polling found nearly 40% of surveyed insulin users reported paying more than $150 per month.

States are also examining PBM practices. Florida has sued several major PBMs and insulin manufacturers, alleging pricing and rebate practices contributed to higher costs for diabetes medications. Iowa, meanwhile, is challenging a court ruling that blocked portions of a state law regulating PBMs.

Paul Pruitt, co-founder of prescription drug procurement company SHARx, argues PBM compensation should be separated from medication prices and that pharmacy benefits should instead be measured by factors including affordability, access and medication adherence.

The survey highlights a broader concern about whether patients have enough information about their out-of-pocket costs before they reach the pharmacy counter.