Patients with Type 1 diabetes who aggressively use insulin to keep their blood sugar in check slash their risk of subsequent kidney failure by half, according to a U.S.-funded study that spanned two decades.

Researchers tracked kidney function in 1,375 patients with the most severe form of the disease who enrolled in the Diabetes Control and Complication Trial starting in 1983. While the study was halted a decade later because patients getting aggressive treatment had fewer complications from the disease, the researchers continued to monitor them to determine the long-term effects. The study previously found fewer cardiovascular complications in patients getting strict diabetes control.

“Tight control early in the course of the disease has long-lasting benefits on all major diabetes complications,” Ian de Boer, the lead researcher and an assistant professor of medicine at the University of Washington in Seattle, said in a telephone interview. “The benefits were from early intensive therapy and they only manifested more than a decade after the treatment began.”

Patients who injected insulin at least three times a day to get their blood sugar to the same level seen in people without diabetes had half the risk of poor filtration and end-stage kidney disease a decade later, according to the study released Saturday by the New England Journal of Medicine. The results show for the first time that treatment can avert the loss of kidney function that leads to organ failure, a process that was previously considered inexorable, de Boer said.

About 25.8 million people in the U.S. have diabetes, when the body doesn’t properly use insulin to convert blood sugar to energy, according to the American Diabetes Association. Less than 10 percent have Type 1, the most serious form where the body’s immune system attacks pancreatic cells that produce insulin. Most diabetics have Type 2, an illness linked to aging, obesity and resistance to insulin.

It’s not clear if the findings of the new study apply to patients with Type 2 diabetes. Those patients typically are older and have other medical conditions, potentially limiting the amount of time they have to benefit from closely regulating their blood sugar, de Boer said.

An earlier study of intensive treatment in patients with Type 2 diabetes was halted because the approach appeared to increase death rates. It may be that damage was already done that couldn’t be reversed, de Boer said.

“Early, when people are relatively complication-free and have a long time to derive the benefits of therapy, is when intensive glucose control is likely to be most effective,” he said.

In the study, 24 patients getting intensive therapy developed impaired kidney function, compared with 46 diabetics getting regular care. Eight developed end-stage kidney disease, down from 16 of those who used insulin to prevent symptoms.

The study, funded by the National Institute of Diabetes and Digestive and Kidney Diseases, was presented at the American Society of Nephrology’s annual meeting in Philadelphia.