(Reuters Health) - Diabetes is becoming increasingly common in the United States, but the risks of complications from the blood sugar disease have declined since 1990, according to a new study.
Better preventive care for adults with diabetes contributed to a 68 percent drop in their risk of heart attacks and a 64 percent drop in deaths from high blood sugar.
The risks of strokes and lower-limb amputations both fell by about one half, researchers found, and there was a 28 percent drop in cases of kidney disease so serious that dialysis or a transplant was required.
However, from 1990 to 2010, while the U.S. adult population rose by 27 percent, the number of adults diagnosed with diabetes tripled, from 6.5 million to 20.7 million, researchers reported in the New England Journal of Medicine.
"I tend to see this as more good news than bad news," lead author Dr. Edward Gregg told Reuters Health. "For the average person with diabetes, the complications are declining and, in some cases, more than expected."
But, "If we don't do something to reduce the incidence of diabetes, we're going to have a lot more diabetes complications down the road," said Gregg, a senior epidemiologist in the Division of Diabetes Translation at the Centers for Disease Control and Prevention in Atlanta.
Dr. Elizabeth Seaquist said she was surprised to see such a precipitous decline in the heart attack rate.
"That's bigger than I would have expected," she told Reuters Health.
Seaquist, president of medicine and science at the American Diabetes Association, was not involved in the new study.
The fact that individual patients are facing a lower risk of complications "is fabulous," she said. "But on a population basis, because of the epidemic, this is a problem that's not going away. We really need to address the whole problem of the epidemic of diabetes."
The researchers based their findings on three databases and the National Health Interview Survey, which poses health questions to about 57,000 U.S. adults each year.
The rates of heart attacks, strokes and lower-extremity amputations among non-diabetic people also declined, they found, but not nearly to the degree seen among those with diabetes.
The declines among people with diabetes were first seen in 1995 and continued in subsequent years.
"These findings probably reflect a combination of advances in acute clinical care, improvements in the performance of the health care system, and health promotion efforts directed at patients with diabetes," the researchers wrote.
"Hardly any of these declines just involve a single factor, and it probably varies by complication," said Gregg.
But the growing prevalence of diabetes meant that, from year to year, the number of cases of most complications increased overall despite improved care.
Compared to 1990, in 2010 there were 59,703 more cases of stroke, 22,703 more amputations and 32,434 more instances of advanced kidney disease among diabetes patients in the U.S.
In contrast, the total number of heart attacks among people with diabetes fell by 4,379 and the number of deaths from hyperglycemia dropped by 529.
The researchers note that the increasing prevalence of diabetes and the aging of the baby-boomer generation suggest the total number of diabetes-related complications "will probably continue to increase in the coming decades."
The study did not look at other complications of diabetes, such as blindness and dangerously-low blood sugar.