There are many forms of plastic in health care. No, I’m not talking about new polymers used for medical implants. I’m talking about financial services.

A new card from Humana and Republic Bank illustrates the continuing integration of consumer personal finance and health care. The new VISA card, private labelled as the HumanaAdvance card, will be offered to Humana’s employer groups for enrollees to use at hospitals, doctor and dentist offices, drugstores and other locations providing health-related products and services.

Of course, as with all plastic, this card comes with its own fine print: 0% interest rate (APR) on purchases paid over six months. What happens after six months, the press release doesn’t say. The card can be used in conjunction with health savings accounts. Republic’s press release empathizes, “We understand that consumers need to bridge the gap on their healthcare expenses and believe our Card is a perfect solution that allows consumers to better budget for their healthcare costs while more easily paying for them over time.” For Humana’s enrollees who regularly fund their HSA and track expenses, this will be helpful.

But the use of plastic isn’t always healthy, at least financially speaking. There’s a growing use of plastic in health care. As plastic’s role in health grows, so does medical bankruptcy. Comptroller General David Walker told a meeting of the Federation of American Hospitals in March that, “If there’s one thing that can bankrupt America, it’s health care.” Credit cards are enabling medical bankruptcy.

About one-fifth of low- and middle-income households with credit card balances cited significant medical expenses as a reason according to Demos and The Access Project, who conducted a study into medical bankruptcy earlier this year.A growing number of Americans, most notably seniors, use credit cards and lines of home equity to pay for medical care in the U.S. Among households ages 65 and older, the average amount of credit card debt more than doubled between 1992 and 2004 to $4,907. Bankruptcy filings in recent years have increased among seniors at a higher rate than among any other age group. Seniors 65 and older represent the fastest-growing group seeking bankruptcy protection, though they made up only 5% of all bankruptcy filers as of 2001.

In their study, Demos and The Access Project said the number of patients using credit cards to pay their medical bills is expected to rise as employers increasingly shift insurance expenses to workers who already face larger insurance copayments and higher deductibles for medicine and treatment.

“The healthcare safety net is made of plastic — its called ‘credit cards’ for many people,” said Mark Rukavina , director of Access Project, which is affiliated with Brandeis University. “It’s a pretty frightening prospect.”

About half (48%) of adults in middle-income families ($35,000 to $50,000 annual income) reported serious problems paying for health care and health insurance. In fact, health care costs are now stretching budgets even for those with higher incomes.

One-third of adults with family incomes between $50,000 and $75,000 a year, and one-fifth with incomes over $75,000 report serious medical bill problems, according to PNC Wealth Management. Wealthy people increasingly believe paying for health care will eat through their assets. Forty-three percent of individuals with at least $500,000 in assets said that health care costs will consume a major portion of their wealth, up from 37 percent in late 2005, according to PNC.

Health Populi’s Hot Points: The graph on the right dramatically illustrates the drastic decline in personal saving rates in the US. Note that in recent years there was “dissaving” — economists’ phrase when spending is greater than income. In dissaving, money can come from personal savings such as money in a savings account, or it can be borrowed. Such borrowing can take the form of credit card spending when the balance isn’t paid off in 30 days. Expect more dissaving, and personal bankruptcy, as Americans age and haven’t saved enough to pay for medical expenses that won’t be covered by health plans.