People with type 2 diabetes may have an insulin-free future to look forward to, suggests a study presented Sunday, but experts say more studies are warranted.

Researchers from the Veterans Affairs Northern California Health Care System in Martinez, Calif., pored through a decade and a half's worth of the medical records belonging to 191 veterans with type 2 diabetes. They found that, of 96 patients who took only oral medications from 1992 to 2007, 55 percent remained on oral drugs to control their blood sugar — what doctors call glucose levels — and never had to take insulin. The other 45 percent eventually switched to insulin, either alone or in combination with oral drugs, according to the study, which was presented at the Endocrine Society's annual meeting in San Francisco.

"Our data suggest that some patients can remain in good glucose control for years using non-insulin, oral diabetic agents," said Arthur Swislocki, the study's author.

Swislocki says the findings give people with type 2 diabetes the encouraging news that they may be able to avoid or delay insulin treatment, which requires an injection and begins when the pancreas is no longer able to produce insulin, a key hormone that helps regulate carbohydrates, fats and proteins.

Robert Vigersky, president-elect of the Endocrine Society and director of the Diabetes Institute at the Walter Reed Army Medical Center in Washington, D.C., agrees the results send a positive message to patients with type 2 diabetes who may want to manage their disease without insulin. But he says the news is more a testimony to the new and improved oral medications that have been made available to people with type 2 diabetes since the early 1990s.

"Fifteen years ago we really only had one category of oral meds, and now we have at least five different classes of medications that work in different ways," Vigersky said.

For similar reasons, the results are not surprising to Mark Schutta, medical director of the University of Pennsylvania School of Medicine's Rodebaugh Diabetes Center in Philadelphia.

"In the time that the study was done, we have had an almost logarithmic increase in the availability of different agents with different actions to treat diabetes," Schutta said.

Schutta says other factors probably also were at play that the study does not delve into. He says it is not a revelation that the authors reported that the less obese, white patients were able to stay on oral medicines longer. "More obese patients have more need for more medication earlier in their disease," he said.

David Nathan, director of the Diabetes Center at Massachusetts General Hospital, said he is not sure that this study is easily interpretable, and that future studies are necessary to determine exactly which oral drugs work best.

"A longitudinal randomized study would be much more informative regarding how patients with type 2 diabetes will do over time on any given regimen," he said.