Consumers who have complex medical diagnoses that requirespecialty drugs should carefully examine the health insurance plansoffered through the public exchange system to avoid incurringhigh costs for those drugs. But that task willbe complicated by inaccuracies on the public exchange website.

That’s the conclusion of an analysis of public exchange plans byAvalere Health. The study, in which researchers went through allavailable plans looking for “hidden” drug costs, found that silverplans in particular tend to place such drugs in specialty tiers intheir 2015 formularies. Avalere said that 17 percent of silver plans contain two or more specialtydrug tiers that will drive up out-of-pocket costs for those patients coveredby the plans.

Even consumers who do their homework to try to avoid such costsmay still wind up incurring them because of inaccurate data aboutout-of-pocket costs for drugs that can be found on the federalexchange website HealthCare.gov.

“Avalere conducted a manual search of plan documents for silverplans because of inaccuracies noted on HealthCare.gov and inassociated data sets,” Avalere said in a release. “Notably,HealthCare.gov reports formulary cost sharing for all plans in afour-tier structure (including only one specialty tier); however,about 35 percent of silver plans do not use four-tier formularies.Because of this discrepancy, consumer costs appearing onHealthCare.gov may misstate actual enrollee financialresponsibility.”

That misinformation on the website could be leading thousands ofinsured individuals into signing up for plans that cost much morethan they believed.

“The mismatch between a plan’s formulary design and thecost-sharing displayed on HealthCare.gov and on state exchangewebsites may be a source of confusion for consumers,” said CarolinePearson, vice president at Avalere.

In other words, consumers who gravitate toward silver plans,which have been the most popular to date, may do better financiallywith a bronze, gold or platinum plan that doesn’t use the specialtydrug tiered design, Avalere said.

“Consumers purchasing these plans need to understand what’s intheir benefit plan and be ready for a substantial out-of-pocketcosts if specialty products are needed,” said Avalere CEO DanMendelson. “While these plans are typical of the exchanges andMedicare Part D where insurers are competing to keep premiums low,they remain rare in the employer market.”