Expanded school health programs with nurse practitioners playing the key role can improve children's health, particularly in inner-city and rural areas that are short of doctors, concludes a five-year study to be released today.

Although implementing a nurse practitioner program means roughly doubling the amount a typical school district spends on health care, the benefits could be dramatic, the study suggests.

"This is the biggest bargain I've seen in the whole health field -- ever," said Dr. Catherine DeAngelis, deputy pediatrics chairman at Johns Hopkins University Hospital in Baltimore, who directed the study.

School-based nurse practitioners can help identify and treat previously undiagnosed health problems, the study found, especially in children less likely to have access to health care outside school: minorities, the poor and those without health insurance.

The goal of the nurses in the program, DeAngelis said, was to provide "a medical home" at school for children who lack regular health care.

Nurse practitioners are registered nurses who receive extra clinical training in the diagnosis and treatment of minor illnesses. They work closely with physicians, and in some states can prescribe medicines.

The $6.5 million National School Health Services Program is the largest effort ever undertaken to assess the value of comprehensive health services in schools, including demonstration projects in 18 medically underserved school districts in Colorado, New York, North Dakota and Utah. It was funded by the Robert Wood Johnson Foundation in Princeton, N.J., the nation's largest private grant-maker in the health care field.

Nurse practitioners in the schools were able to detect a range of health problems, including ear infections, vision problems, hearing loss and scoliosis (curvature of the spine), most of which had not been diagnosed previously, the study found. About 96 percent of the problems were resolved, either by treatment right in the school or referral to a community doctor, which is "dramatically better" than in the typical school, the study found.

Immunization rates in many schools were raised dramatically to more than 90 percent. Record-keeping improved. Minor illnesses such as sore throats and minor injuries from accidents were treated without a needless, expensive trip to the doctor's office or emergency room.

Children were less likely to miss school, and parents less likely to miss work to take them to a doctor -- an increasingly important concern, since nearly 60 percent of school-age children have mothers who work.

"The beautiful part of it is that this is a captive audience," DeAngelis said. "The kid has to be there. You have a built-in long-term followup.

For example, if a nurse practitioner discovers that a child needs glasses, the nurse can work directly with the teacher to make sure that the child actually uses the glasses in class. A school-based nurse practitioner can also help educate children about health issues and coordinate efforts by teachers and parents to help students to deal with learning disabilities.

"It doesn't mean nurses do things better than doctors," said DeAngelis, a pediatrician with a background in nursing. "The key is: It's a team, a doctor-nurse-health aide team."

Although some doctors worried that the nurse practitioners would cost them business, DeAngelis said, most were delighted with the results. They were spared needless referrals, and patients who did need care arrived with much of the time-consuming diagnostic details taken care of by the nurse practitioners.

The demonstration was so successful that communities with more than 85 percent of the students in the program have elected to continue it with their own funds, now that the original funding has run out.

In Colorado, school districts in all three demonstration sites have used county and private funds to keep the program alive, said Dorothie Clark, of the Colorado Department of Health.

The program improved the quality and accessibility of health care and encouraged preventive health and health education in the schools, Clark said.

"Time and again, in routine screening or sports physicals, we'd pick up cases of problems that had never been identified and that no one had followed," said Kathleen Stillion-Allen, a nurse practitioner and school health consultant in the Utah Department of Health. Those included cardiac arrhythmias (irregularities in the heart beat) and orthopedic problems, she said, and immunization rates roughly doubled at the high school level.

School health programs have been curtailed in recent years. "In a time of budget cutting, school health services may be the first to go," concluded a Public Health Service report to Congress in 1981.

Significant physical and behavioral problems were overlooked in many schools, as doctors saw only the most seriously ill children, DeAngelis said.

"What you don't see," she said, "you don't know exists."

The dwindling number of school nurses lack the time, support and training to deal fully with serious child health problems at the school, DeAngelis said. In 1980, only 2 percent of school nurses were nurse practitioners, according to the American Nurses Association.

"In most schools today," she said, "a school nurse runs between eight schools, makes sure you're immunized, sort of, pushes a lot of paper around and looks in your hair twice a year for nits."

The Johnson Foundation study included a geographic and socioeconomic variety of school districts. They ranged from a sprawling Denver suburb to Utah's Tooele County, which is larger than Rhode Island and Massachusetts combined; from south-central North Dakota, where many residents live 60 miles from the nearest doctor, to the inner city of Newburgh, N.Y., an economically depressed city on the Hudson River.

DeAngelis said the findings are relevant to any school district with a lot of kids who lack "a medical home."

Most American children have access to a doctor if they're seriously ill. But the school-health study concluded that "there are residual groups of children who still lack access and that even for children with private physicians, the program could provide supplemental care."

Although the health benefits are demonstrable, it is not clear whether expanded health services in the schools would lower or raise total health costs, analysts cautioned.

They could save money by reducing emergency room visits and use of doctors for routine care and by preventing illness and by diagnosing disorders promptly, when treatment is more effective and less expensive. But these savings might be offset by the cost of the added service and care for previously undiagnosed problems.

School districts spend an average of $25 per child per year on health. The cost of the expanded program tested by the Robert Wood Johnson Foundation was higher, ranging from $43 to $82 per child.

That's a small price to pay for improving the health of children, in DeAngelis' view.

"You can't go to the emergency room once," she said, "and get charged less than that."