NEW YORK — In the midst of the diabetes epidemic, federal researchers reported sweeping progress in combating some of the most devastating complications of type 2 diabetes Wednesday, finding that rates of heart attacks, strokes, kidney failure and amputations declined sharply over the past two decades.

The research shows the rates of heart attacks and strokes among diabetics fell by more than 60 percent and confirms earlier reports of drastic declines in diabetes-related kidney failure and amputations.

The drop is mainly attributed to better screening, medicines and care. The improvements came even as the number of U.S. adults with diabetes more than tripled in those 20 years and is now nearly 26 million, placing a heavy burden on the health-care system. An additional 79 million Americans have pre-diabetes, which means they are at high risk of developing the disease.

Diabetes is a disease in which sugar builds up in the blood. The most common form is tied to obesity, and the number of diabetics has ballooned with the rise in obesity. The obese are already at higher risk for heart attacks and strokes. But diabetics seem to have more narrowing of their blood vessels — a condition that can further foster those problems.

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While researchers had patchy indications that outcomes were improving for diabetic patients in recent years, the study, published in The New England Journal of Medicine, documents startling gains.

“This is the first really credible, reliable data that demonstrates that all of the efforts at reducing risk have paid off,” said Dr. David Nathan, director of the Diabetes Center at Massachusetts General Hospital, who was not involved in the study. “Given that diabetes is the chronic epidemic of this millennium, this is a very important finding.”

Researchers from the Centers for Disease Control and Prevention (CDC), who wrote the study, estimate that diabetes and its complications account for about $176 billion in medical costs every year.

Researchers said the declines were the fruit of years of efforts to improve the health of patients with type 2 diabetes. Doctors are much better at controlling the risk factors that can lead to complications — for example, using medicine to control glucose, lipids and blood pressure — health experts said.

What is more, a widespread push to educate patients has improved how they look after themselves. And a major effort among health-care providers to track the progress of diabetes patients and help steer the ones who are getting off track has started to have an effect.

Edward Gregg, a senior epidemiologist at the CDC and the lead author of the study, said it used four federal data sets — the National Health Interview Survey, the National Hospital Discharge Survey, the U.S. Renal Data System, and Vital Statistics — for a 20-year period to give the most comprehensive picture of diabetes outcomes.

“This is the first time we’ve put the full spectrum together over a long period of time,” Gregg said. He pointed out that heart attacks, which used to be the most common complication by far, had dropped down to the level of stroke, which also fell.

“We were a bit surprised by magnitude of the decrease in heart attack and stroke,” he said.

Beyond the declines in the rates of heart attacks and deaths from high blood sugar, the study found that the rates of both strokes and lower extremity amputations — including upper and lower legs, ankles, feet and toes — declined by about half.

Rates for end-stage kidney failure fell by about 30 percent.

The study did not measure blindness, another critical diabetes complication.