The poorest employer-insured families spend nearly one-fifth of their income on average on premiums and co-pays if not everyone on their plan is healthy.
If everyone's healthy, that same family would spend about 13% of their income on premiums and out-of-pocket health costs. As family incomes grow, their rate of healthcare spending decreases, according to new by the Kaiser Family Foundation and the Peterson Center on Project Japan.
The authors Gary Claxton, Bradley Sawyer and Cynthia Cox argued the trend could be part of "what is fueling interest in proposals like Medicare-for-all and options for employers and/or workers to buy into Medicare."
For healthcare experts, the finding doesn't say much that's surprising. But it draws attention to the overall trajectory.
"The affordability trends in the employer market are driven by healthcare costs rising a lot faster than the median income," said Sara Collins, vice president of healthcare coverage and access at the Commonwealth Fund.
The Commonwealth Fund through its Biennial Health Insurance Survey has tracked how employer insurance benefits have grown skimpier since 2003. The number of adults deemed underinsured on their employer plans has between then and 2018.
Meanwhile, employer-insured families who spent enough on healthcare to meet their deductibles saw their expenses nearly double as a percentage of their income over the past decade.
Premium and deductible costs have also risen to nearly 12% of the median income in 2017, up from nearly 8% in 2008.
Collins said the implications of these higher costs raise "a fundamental dilemma for employers" as their employees are becoming more likely to skip a doctor's visit or a prescription.
"They're designing benefits to shift more costs to the employees, potentially undermining the productivity of their employees," she said.
Joseph Antos of the American Enterprise Institute criticized the thesis of the Kaiser paper as stating the obvious: that healthcare spending, like any spending, will always represent a higher percentage of a poor person's income than it will for someone who earns more.
But he also advocated for a fix to the disparity between what rich people and poor people have to pay out in terms of their earnings, which stems from the employee insurance tax benefit known as the tax exclusion.
"The idea of providing a subsidy to encourage people to get coverage on the job may not be a bad idea, but the way it's been implemented is to favor high-wage workers not low-wage workers," Antos said. "It's inefficient and not fair. We should be helping lower-wage workers first."
Growing discontent within the employer market could pose the strongest political threat to the status quo of coverage.
Since most Americans get their health insurance coverage through work, conventional wisdom holds employer-sponsored insurance as the bulwark against a complete overhaul like Medicare for All, which got a big push in the 2016 presidential election from Sen. Bernie Sanders (I-Vt.).
While it's still considered a political long shot, the policy has entered the political vernacular. Last week, insurance stocks tumbled after Sanders re-introduced his Medicare for All legislation.
Sanders is running for president, and the bill's co-sponsors include other Democratic presidential contenders in the upper chamber—Sens. Kamala Harris of California, Elizabeth Warren of Massachusetts, Cory Booker of New Jersey, and Kirsten Gillibrand of New York.
As a pre-emptive measure, the industry-backed Partnership for America's Health Care Future is running a six-figure media campaign to push back against Medicare for All as well as various public option proposals.
On the other side of the political spectrum, the industry is also trying to block cost-cutting efforts from the Trump administration and Congress: from a site-neutral payment policy for hospitals, to an international reference pricing model for pharmaceutical manufacturers, and elimination of drug rebates to pharmaceutical benefit managers.
While Democratic leadership is focused on Obamacare as opposed to Medicare for All or other proposals, the cost issues haven't been solved yet there either. Premiums remain high for people who don't qualify for subsidies. Democrats want to boost insurance subsidies for more people across higher income levels, as the government's costs for the exchange markets have continued growing.
Collins, who suggested policy options that include a fix to the "family glitch" in the ACA and requiring employers to restrict high-cost drugs from coverage, said that any funding boost for coverage "absolutely needs to be paired with efforts to lower underlying costs."
"And the major culprits are provider prices and prescription drugs," she said.