Insurers offering new Obamacare marketplace health plans that set HIV drug cost-sharing levels in the highest tier may be doing so to discriminate against people living with the virus. Publishing their findings in the New England Journal of Medicine, researchers analyzed “adverse tiering”—when all the drugs for a particular condition are placed in the highest cost-sharing level—in 12 states in the federal marketplace.

The researchers compared plans in six states that have been named in a complaint about adverse tiering to the U.S. Department of Health and Human Services (Delaware, Florida, Louisiana, Michigan, South Carolina and Utah) as well as plans in the six most highly populated states that did not have insurers mentioned in the complaint (Illinois, New Jersey, Ohio, Pennsylvania, Texas and Virginia). They compared the cost-sharing levels for nucleoside reverse transcriptase inhibitors (NRTIs, or nukes).

Twenty-five percent of the 48 plans analyzed used adverse tiering for NRTIs, the study authors found HIV-positive members of these plans paid an average of triple the amount for antiretrovirals as those in non-adverse tiering plans. The difference between name-brand and generic drugs was still nearly $2,000 per year. The premiums in the adverse tiering plans did tend to be lower than the other plans. However, the cost-sharing for HIV medications in the adverse-tiered plans meant that HIV-positive member would pay an average of $3,000 more per year than in the non-discriminatory plans.

“Eliminating discrimination on the basis of pre-existing conditions is one of the central features of the Affordable Care Act (ACA),” Doug Jacobs, MD/MPH candidate at the Harvard T.H. Chan School of Public Health and lead author of the study, said in a press release. “However, the use of formularies to increase costs and dissuade those with preexisting conditions such as HIV from enrolling in the plan threatens to at least partially undermine this goal of the ACA.”

To read the press release, click here.

To read the study, click here.