A new complaint claims that insurers may be flouting a key provision of the Affordable Care Act that prevents discrimination. As part of health-care insurance reform, this provision prevents insurers from denying coverage or pricing their plans based on pre-existing conditions.

The goal of the provision is noble in that it aims to insure hundreds of thousands of patients that were inadequately covered, or rejected, by insurers previously; however, insurers facing looming costs may be inadvertently steering patients with life threatening disease like HIV away from plans.

In May, Tampa based The AIDS Institute (TAI) filed a complaint with the Department of Health and Human Services stating that silver plans (those most commonly chosen) offered by Aetna's (NYSE:AET) CoventryHealth, Cigna (NYSE:CI), and Humana (NYSE:HUM) in Florida ostensibly sought to reduce the number of applicants with HIV by requiring "inordinately high co-payments and co-insurance for medications."

Source: PhRMA and Avalere Health

A troubling trend
Including HIV medication in the most expensive tiers of an insurer's drug formulary seems to be driven by fear over surging costs tied to next generation HIV treatments from companies including Gilead (NASDAQ:GILD).

According to major specialty drug distributor Express Scripts, HIV medicines were among the most costly to Obamacare exchange plans in the first quarter. That's not only because drugs like Gilead's top-seller Truvada cost more than $10,000 per year, but because a larger percentage of HIV patients are enrolling in ACA plans relative to non-ACA plans.

Of those HIV patients that are signing up through Obamacare, many had been previously receiving their NNRTI, NRTI, protease inhibitors and other HIV drugs through charities or lower-cost corporate discount programs. Now that they're covered by their plans, they're facing out-of-pocket charges that are as high as 50% of the drug's cost.

Source: Gilead Sciences

Challenging changes in treatment
While HIV patients lived an average of 10 years after diagnosis in the early 1990's, patients diagnosed today can expect to live twice as long and new therapies are expected to increase longevity even more over the coming decade.

Companies like Gilead, which markets a handful of top selling HIV medications that generate $9 billion in annual sales, and Merck (NYSE:MRK), which markets the widely-used Isentress, are developing new drugs that work better, but are likely to carry a bigger price tag.

Additionally, efforts to improve prevention and early diagnosis are ramping up and could increase the diagnosed patient population given that 200,000 out of the more than 1 million people estimated in the U.S. with HIV remain un-diagnosed.

A combination of more, longer living patients, taking increasingly more expensive drugs is squeezing payers like Aetna, Cigna, and Humana; particularly, in exchange plans that by their nature are expected to be sold at a lower cost.

Finding a solution
TAI hopes its complaint will boost scrutiny of how plans are designed in the future. If HHS determines that high co-payments for life saving medications effectively discriminate, insurers will need to respond with higher monthly premiums to make up for lower co-payments.

However, if it remains business as usual, drugmakers like Gilead may search for a work around that overcomes the hurdles created by high out-of-pocket expenses that may make more likely inadequate adherence to prescribed treatment.

In New York, Gilead and Bristol-Myers Squibb have already agreed to discount the cost of their medicine as part of a bold plan to increase the number of people taking HIV medication and effectively prevent new infections. That suggests that drugmakers are willing to engage in price concessions in exchange for script growth.

Fool-worthy final thoughts
The ACA is designed to increase coverage so that people who need treatment can afford it, but in some cases determining affordability goes much further beyond calculating a plan's monthly premium.

Insurers like Aetna, Cigna, and Humana are prevented from pricing individual plans sold in the marketplace based on each member's individual health, so in many cases insurers appear to have adopted a conservative approach that could change over time as more younger and healthier people sign up.

Regardless, payers of all types will be increasingly pressured as new drugs win approval. Express Scripts estimates that spending on HIV medication will grow by 16% in 2015 and another 13% in 2016.