WASHINGTON — The Obama administration said Wednesday that a pilot program aimed at preventing people from developing diabetes would save money if expanded, and that it could soon be covered by Medicare. It is the first time an experimental prevention initiative has met the test to become part of the huge federal health care insurance program for older Americans.

In their announcement, officials said that Medicare could one day help cover services for 86 million Americans with a condition known as prediabetes. Those people have elevated levels of glucose in their blood, but not high enough for a diagnosis of diabetes, one of the nation’s leading causes of death.

The five-year, $11.8 million pilot demonstrated that older people could lose weight through lifestyle counseling and regular meetings that encourage healthful eating habits and exercise, an improvement that helps stave off diabetes. On average, the more than 7,700 participants lost about 5 percent of their body weight.