Millions of patients could soon be filing into hospitals, some who have little to no experience using insurance or dealing with doctors. Who are these people and what should providers do to prepare for their arrival?

Nov. 13 is the deadline for states to file plans to start their own insurance exchanges as part of the Affordable Care Act. Thirteen have already done so, with the other 37 expected to have the federal government involved in running their exchanges, according to a recently released report by PricewaterhouseCoopers.

Some 12 million Americans are expected to enter the health care system next year and 29 million by 2021. Analyzing data from both the U.S. Census Bureau and Agency for Healthcare Research and Quality, researchers found that these new patients will mostly be white, younger and in relatively good health.

Many of the uninsured come from low-income backgrounds, and about 30 percent won't speak English as their primary language. As such, hospitals will need to tailor their offerings to meet the needs of some very different customers, says Vaughn Kauffman, principal at PwC and leader of its payer advisory practice.

"What they view as valuable to them is going to differ from what the insured population does today," he says. "Simplifying the message for health care is important for this group. They haven't had to navigate it or they don't navigate it as much, and so educating them is going to be important."

Initially, PwC doesn't expect a huge wave of patients flowing into hospitals, since about 88 percent reported being in good health. But there could be some "pent-up demand" for health services, which could require additional hours for routine assessments.

Vaughn also emphasized the importance of transparency, putting health care information online, and letting these new patients behave like consumers, as they've done when shopping for other products. Many will be much more price-conscious and factoring in cost when making decisions.

"The exchange starts to shift the industry to more of a retail model," Vaughn says. "And other industries are really starting to dictate what health care needs to do, in terms of access to information via mobile devices and the availability of information to cost compare. That kind of transparency is going to be put more in demand of the provider and health care in general."

Many of the new patients have unstable incomes, and as such, they'll cycle back and forth between Medicaid and exchange insurance, PwC predicts. Hospitals must stay diligent — using outreach programs, targeted products and customer support — to avoid disrupting the continuum of care. Providers with their own health plans and accountable care organizations will have the early lead in the marketplace, the report says, as they'll have the advantage in coordinating care and support services from multiple places.

Here are some other highlights from the report, which can be found here.

  • About 32 percent of the uninsured will sign up for coverage through Medicaid, 45 percent through the exchange, and around 25 percent will use employer-sponsored plans.
  • The median age of the uninsured is 33 years old; 85 percent do not have a college degree; and 42 percent are employed full time.
  • The median income is about $18,542 for an individual and $38,263 for a family of four, 166 percent of the federal poverty level.
  • By 2021, 40 percent of the exchange participants will come from five states: California, Texas, Florida, New York and Illinois.
  • Exchanges will range in size from 100,000 in Maine to 3.5 million in California.