Patients with HIV could pay as much as $3,000 a year more for drug coverage on some insurance plans compared with others listed on the federal health insurance marketplace. That gap isn’t a symptom of a difference in drug prices; it’s built into the pricing scheme of certain plans. Within those plans, all available drugs for HIV fall into one tier of coverage — the one with the highest copay. That means patients essentially have no way to opt for a drug with a lower percentage of out-of-pocket expense.

The practice is called “adverse-tiering” and has also been found to impact patients with diabetes, cancer, rheumatoid arthritis and mental illness. It represents a new threat to the spirit of the Affordable Care Act and the Obama administration's efforts to ensure that patients do not face discrimination based on age or pre-existing conditions. The administration has proposed rules that would take effect in 2016 to stamp out these unfair practices. In the meantime, patients enrolled in the problematic plans may unwittingly be paying thousands more dollars each year than others for the same treatment.

"I think for the individual patient, it would be really difficult to figure this out," Douglas Jacobs, a master's degree student in Harvard University's School of Public Health who has examined this issue in-depth, says. 

A study published Wednesday in the New England Journal of Medicine by Jacobs and Harvard health economist Benjamin Sommers shows that 25 percent of the health insurers they studied are guilty of placing all drugs for HIV treatment in the top tier of coverage, which requires at least a 30 percent copay. The team found that people on these plans paid an average of three times more for their medications than patients on plans that did not use this scheme. This added up to an extra cost of $3,000 a year for patients on discriminatory plans. Had a few of their drugs been classified into lower tiers, patients could have bought them at a lower out-of-pocket expense.

Tiers of coverage are often used by insurers to encourage their customers to choose generic medicines over brand names. By grouping generics in a lower tier with a higher percentage of coverage, insurers can save money for their company and for their customers. But pushing both generic and name brand drugs into a tier with the highest costs has no practical purpose except to discourage clients with expensive medications from signing up, health care rights advocates say.

Such a ploy would directly oppose the stated mission and rules of the Affordable Care Act, though it would not necessarily be out of character for insurers, says Jacobs. "There's no way to read the insurance company's minds and say this is their intent. Our research looks at the impact," he says. "If it was to discourage enrollment by those with pre-existing conditions, it would be consistent with [insurers'] behavior prior to the Affordable Care Act." The research team was not willing to share which companies were included in their analysis.

Jacobs was tipped off to this practice by a complaint filed last May with the U.S. Department of Health and Human Services by the AIDS Institute and the National Health Law Program. Those organizations voiced concern about four insurers in Florida – Coventry Health Care Inc., Cigna, Humana and Preferred Medical  — that were listed on the federal health insurance marketplace and suspected of discriminatory pricing. "When I read it, what I was really curious about was, is this going on only in Florida or is this a nationwide phenomena?" Jacobs says. All of the insurers mentioned in the original complaint have since revised their plans to lower drug costs for HIV patients, as Preferred announced just last week that it would place a $200 per month cap on each of four drugs, according to the Miami Herald.

He and Sommers analyzed plans in 12 states, including six that were referenced in the complaint and six that were not. They searched for a class of drugs commonly prescribed to HIV patients called nucleoside reverse-transcriptase inhibitors. All of the plans they examined were listed on the federal marketplace, though Jacobs says there is no guarantee that insurers aren't using the same tactics within state marketplaces.

Clare Krusing of America's Health Insurance Plans, a trade group for insurers, told the Washington Post that the study fell short because it focused on one type of plan — "silver" — that is the most popular but did not include other plans available through the marketplace and which might offer better benefits for HIV patients.

Last year, Avalere Health, a health care analytics company, published a study showing that the problem goes beyond HIV: 20 percent of plans they examined had discriminatory pricing for at least 10 classes of serious illnesses including cancer, autoimmune diseases and bipolar disorder. All of the drugs in these classes required a minimum copay of 30 percent. Regardless of copay, the authors found that 20 percent of plans they examined put drugs for multiple sclerosis, rheumatoid arthritis and Crohn’s disease into the highest possible tier; 25 percent to 35 percent of plans did the same for HIV/AIDS.

“This study supports what we see as an alarming trend of pricing structures that have an extremely adverse impact on the patients with some of the most debilitating, life-threatening and chronic conditions,” Alan Balch, CEO of the Patient Advocate Foundation, said in a statement. "We applaud any efforts on the part of the Department of Health and Human Services to monitor discriminatory pricing, but we feel strong and immediate action needs to be taken to address this issue."

The Obama administration has proposed new rules for 2016 that would require each insurer to go before a review committee to determine that their plan “does not substantially discourage enrollment by any group of enrollees” and asks that companies publish tiering structures for prospective enrollees to see before they sign up.

Sommers and Douglas have suggested a few solutions of their own. They think it would help to create a class of drugs for chronic illnesses like HIV that insurers must cover in a tier with a low copay. Another step might come in requiring insurers to cover a set percentage of all drug costs within a given plan, making it so that insurers would have to lower the copay on one drug if they wished to raise it on another.

"This is clearly an issue. The elimination of discrimination based on pre-existing conditions was a huge victory of the Affordable Care Act so making sure that becomes a reality will require a lot of vigilance and oversight," Jacobs says. This year, 9.5 million people have enrolled in health insurance plans through the government and a month still remains in the sign-up period.