We have ample evidence that health-care costs are increasingly shifting away from employers and onto employees. Deductibles — the amount an enrollee has to pay before the insurer will cover medical bills — have risen sharply over the past decade. Even after adjusting for inflation, one recent analysis finds deductibles have doubled from $1,240 for family coverage in 2002 up to $2,491 in 2013.

A new Kaiser Family Foundation study explores one big repercussion of that trend: lots of American families wouldn't have enough cash on hand to cover the average deductible.

The KFF study looked at the liquid assets of American families — things like savings accounts, mutual fund investments, savings bonds, and other things that could quickly be converted into cash— and compared them to different deductible sizes that turn up in today's insurance market.

The key takeaway is there are lots of families that wouldn't be able to afford these types of deductibles. KFF finds that 37 percent of American families don't have more liquid assets than a medium-range deductible ($1,200 for individual coverage, $2,400 for family) and 49 percent couldn't cover a higher-range deductible ($2,500 for an individual, $5,000 for a family).

Of course, there are lots of insurance subscribers who never meet their deductible. But for those who have more medical needs, the KFF research suggests that their coverage might offer scant financial protection.

"Deductibles may provide a sensible incentive for people to be prudent consumers of health care," KFF president Drew Altman writes. "But with so many people with private coverage lacking the funds to meet growing cost-sharing obligations, they can pose a serious financial burden and sometimes be a barrier to care for many, especially lower- and moderate-wage workers."