Image: Cosmetic surgery © Jutta Klee, fStop, Getty Images

Credit card issuers are stepping up their marketing of health care cards and lines of credit that help borrowers finance costly elective medical procedures. The cards, which typically boast initial interest rates of 0%, are targeted to clients of plastic surgeons, dentists and even veterinarians.

Though they help some people pay for important procedures, the cards come with a number of drawbacks that may not be apparent at sign-up, including rates that can quickly spike.

Some big firms are ramping up their offerings. Citigroup offers the Citi Health Card, while JPMorgan Chase pitches ChaseHealthAdvance, a line of credit aimed at helping customers finance elective health procedures such as corrective eye surgery. Even General Electric's GE Money unit offers a card, called CareCredit.

In the past two years, such specialty cards have swelled in popularity among health care providers, driven, in part, by baby boomers to finance devices like hearing aids and expensive procedures not covered by insurance, says Gina Calabrese, a professor at St. John's University School of Law in New York.

The card issuers don't disclose their outstanding loan volume, but GE's CareCredit card -- the field's largest -- is accepted by roughly 140,000 health care providers, a 40% increase from three years ago.

A growing number of patients at plastic surgeon Jeffrey Spiegel's office in Boston, for example, have started using the CareCredit card to finance procedures like Botox, says Kelly Bennett, the practice's coordinator. Veterinary Emergency and Referral Group, a specialty animal hospital in Brooklyn, N.Y., gives patients who balk at expensive treatments for pets the option of paying on a CareCredit card.

In part, the card issuers are taking advantage of gaps in health insurance policies for procedures like dental implants, corrective eye surgery and cosmetic surgery. By 2015, patients could be forking over roughly $150 billion in out-of-pocket health care costs, according to consulting firm McKinsey, up from an estimated $45 billion in 2010.

Citigroup's card allows patients to start treatments immediately instead of having to delay expensive procedures, says spokeswoman Elizabeth Forgarty, adding that the card's growth has been "robust." JPMorgan Chase's line of credit "offers consumer financing for medical needs and health care needs that may not be covered by insurance," spokesman Steve O'Halloran says.

For providers, the cards promise relief from billing headaches and the expense of wrangling cash from patients. The cards also can drive up business, since they allow patients to finance expensive elective procedures they might otherwise forgo.

But for some patients, the cards can lead to medical-billing nightmares, according to Minnesota Attorney General Lori Swanson, who says her office has seen a surge in complaints about the cards over the past year.