The Spitzer administration is cracking down on the number of hospitals that perform weight-loss surgery, an increasingly popular procedure performed in more than a dozen hospitals citywide.

Citing quality control and cost, the state will restrict how many institutions may perform bariatric surgery, even as the number of patients seeking the surgery nationwide and in New York City has grown exponentially in recent years.

State health officials said they plan to use their “selective contracting” authority to limit Medicaid reimbursement for such surgeries to five hospitals in New York City. Currently, 27 hospitals in the city perform bariatric surgery, in which doctors reduce the size of a patient’s stomach to limit the amount of food that can be consumed.

“Through our purchasing authority, we can purchase high-quality, cost-efficient care, and that’s the driver,” the state’s Medicaid director, Deborah Bachrach, said. The state plans to issue a request for proposals and select the five hospitals by this fall.

The state also plans to limit the contracts awarded to hospitals that perform breast cancer surgery, but officials outlined far looser guidelines for the selective contracting for that procedure and said the state would reimburse hospitals that perform at least 30 procedures annually.

The move to limit hospital contracts for bariatric surgery is part of a larger effort to alter the state’s $46 billion Medicaid program, one of the most costly nationwide. Bariatric surgery is sometimes seen as a revenue stream for hospitals, which can be reimbursed thousands of dollars for each procedure.

Some hospital executives cringed at the notion that patients could lose access to care.

“For us, there is a major access issue,” the president of the city’s Health and Hospitals Corp., Alan Aviles, said. “If they stop paying us to do bariatric surgery, then we obviously could not continue to do that.”

He said limiting the procedure to five hospitals could present geographic barriers for severely obese patients who have difficulty traveling. HHC currently performs weight-loss surgery at three hospitals, including Coney Island Hospital, Harlem Hospital Center, and Jacobi Medical Center. The system had been considering a fourth program, Mr. Aviles said, adding, “The mobility hurdle is not insignificant.”

Nationwide, the number of weight-loss surgeries has greatly increased in recent years, with an estimated 205,000 surgeries having been performed in 2007, up from 103,200 in 2003. In 2001, doctors performed 47,200 bariatric surgeries, up from 16,200 in 1992, according to the American Society for Metabolic and Bariatric Surgery.

Doctors said the demand for weight-loss surgery has been fueled by the nation’s obesity epidemic. “Each year we see a significant increase in the number of American citizens that enter into the category of obese or severely obese,” a past president of ASMBS, Dr. Philip Schauer, the director of the bariatric and metabolic institute at the Cleveland Clinic, said.

Candidates for weight-loss surgery must be severely obese, meaning at least 100 pounds overweight; they must have a related health condition such as diabetes or high blood pressure; they must demonstrate a failure to lose weight by other means, and they must be psychologically stable.

“There’s no way five hospitals are going to be able to do very many cases,” Dr. Schauer said.

Still, some said the state’s effort was in line with a “center of excellence” approach implemented in other areas of medicine, such as cardiac care. In 2006, the Centers for Medicaid and Medicare announced it would reimburse hospitals for weight-loss surgery only if the hospital was designated a center of excellence by the American College of Surgeons or ASMBS. To be considered a center of excellence, a hospital must meet data-reporting requirements and it must utilize equipment, including toilets and chairs, to accommodate heavier individuals.

Half a dozen hospitals in New York City already have such designations, including Lenox Hill Hospital, where doctors perform more than 600 weight-loss surgeries annually. Currently, Lenox Hill does not operate on Medicaid patients because reimbursement is too low. “I would love for us to be able to contract and be one of the five centers, but I need the resources to help those people,” the hospital’s chief of obesity surgery, Dr. Mitchell Roslin, said.

Other doctors said that without Medicaid reimbursement their programs could not exist, and they expressed concern over a loss of funding. In describing the concern, they stressed the demand for bariatric surgery.

“For us, it would be unthinkable that we couldn’t do it,” the interim chairman of surgery at Montefiore Medical Center, Dr. Arnold Berlin, said. Montefiore physicians perform more than 300 bariatric surgeries each year. “It’s a service we really need to provide,” he said, citing the prevalence of diabetes and obesity in the Bronx. Montefiore recently became a center of excellence.

Dr. Berlin said selective contracting would ultimately benefit patients by consolidating the procedures among doctors who are expert in the field. Surgery on obese patients is complex, he said, adding, “For someone who does it once in a while, it’s like a learning experience every day.”

State officials stressed that patients would not lose access to bariatric surgery. “We can’t limit bariatric surgery to five hospitals and then not have a hospital for that patient to go to,” Ms. Bachrach said.