You’ve probably heard somebody say, “assisted living is the new nursing home.” A new study suggests that, in important ways, it is true.

People living in residential care communities, including assisted living, care homes, or adult group homes, look a lot like those who once lived in nursing homes. They suffer from serious chronic conditions, need assistance with daily activities such as bathing or dressing, and many visit emergency departments or are hospitalized over the course of a year.

More than 730,000 people lived in these communities in 2010, according to a new study by the Centers for Disease Control. That’s about half as many as lived in nursing homes. But the nursing home population declined by about 20 percent from 2000 to 2010, while residential care, which operates with few federal regulations and is often much less costly, has seen a boom in population.

More than eight in ten people living in these facilities are over 75, and more than half are older than 85.

Two thirds lived in these facilities for at least one year, and one-third were residents for four years or more. The average length of stay was more than 2.5 years.

The cost? For facilities that care only for dementia patients, the annual cost approached $54,000 in 2010.  Facilities without dedicated dementia units cost about $35,000 annually. Most residents pay out of pocket. About one-in–five received some Medicaid benefits in 2010 (although new Medicaid is now paying for more assisted living under home and community based waivers, a change that is likely to increase that percentage).

More than 40 percent of residents have Alzheimer’s disease or some other dementia, and one-third have heart disease. Two-thirds need help with bathing and half need assistance getting dressed. More than one-third will visit a hospital emergency department over the course of a year, and one-quarter will be admitted to the hospital.

It’s no surprise that with residents this frail, nearly all residential care communities employ personal care aides and one-third have at least one nurse on staff.

Yet, residents typically get little care from these aides or nurses. They received an average of a bit more than 2 hours of care a day from personal assistants, and only about 5 minutes of care from registered nurses.

Of the 31,000 residential care facilities in the US, half have 10 beds or less. Those small facilities are far more common in the west, where two-thirds have less than 10 beds. By contrast, in the northeast, nearly three-quarters have 25 beds or more. Nationwide, more than 80 percent are private, for-profit facilities.

But while all facilities require some staff training, the level varies widely. Two-thirds required less than two weeks of training while about one-in-five demand more. Four percent of facilities required no training at all. On average about 40 percent of personal care aides leave their jobs each year.

Except for people who need a high level of medical or skilled nursing care, these residential care facilities increasingly are the institutional living choice of consumers—at least for those who can afford to pay out-of-pocket. They tend to be more comfortable than nursing homes, less regimented, and more home-like. Because they are less regulated, they often cost less. But residents may not have necessary quality and safety consumer protections.

There is wide variation in quality, cost, and skill level of staff. Some residents pay for private duty aides to supplement the limited services provided by facility staff. For those who do, the cost can meet or even exceed the cost of a nursing home.

The CDC snapshot of residential care is a useful benchmark for consumers. But, as always, if you are thinking of this kind of care for a loved one, nothing is better than a personal visit.