FRIDAY, Nov. 26 (HealthDay News) Death rates have dropped significantly in people with type 1 diabetes, according to a new study.
Researchers also found that people diagnosed in the late 1970s have an even lower mortality rate compared with those diagnosed in the 1960s.
"The encouraging thing is that, given good [diabetes] control, you can have a near-normal life expectancy," said the study's senior author, Dr. Trevor J. Orchard, a professor of epidemiology, medicine and pediatrics in the Graduate School of Public Health at the University of Pittsburgh, Penn.
But, the research also found that mortality rates for people with type 1 still remain significantly higher than for the general population -- seven times higher, in fact. And some groups, such as women, continue to have disproportionately higher mortality rates: women with type 1 diabetes are 13 times more likely to die than are their female counterparts without the disease.
Results of the study are published in the December issue of Diabetes Care.
Type 1 diabetes is an autoimmune disease that causes the body's immune system to mistakenly attack the body's insulin-producing cells. As a result, people with type 1 diabetes make little or no insulin, and must rely on lifelong insulin replacement either through injections or tiny catheter attached to an insulin pump. Insulin is a hormone that allows the body to use blood sugar.
Insulin replacement therapy isn't as effective as naturally-produced insulin, however. People with type 1 diabetes often have blood sugar levels that are too high or too low, because it's difficult to predict exactly how much insulin you'll need. When blood sugar levels are too high due to too little insulin, it causes damage that can lead to long term complications, such as an increased risk of kidney failure and heart disease. On the other hand, if you have too much insulin, blood sugar levels can drop dangerously low, potentially leading to coma or death.
These factors are why type 1 diabetes has long been associated with a significantly increased risk of death, and a shortened life expectancy.
However, numerous improvements have been made in type 1 diabetes management during the past 30 years, including the advent of blood glucose monitors, insulin pumps, newer insulins, better medications to prevent complications and most recently continuous glucose monitors.
To assess whether or not these advances have had any effect on life expectancy, Orchard, along with his student, Aaron Secrest, and their colleagues, reviewed data from a type 1 diabetes registry from Allegheny County, Pennsylvania. The registry contained information on almost 1,100 people under the age of 18 at the time they were diagnosed with type 1 diabetes.
The children were sorted into three groups based on the year of their diagnosis: 1965 to 1969, 1970 to 1974 and 1975 to 1979. As of January 2008, 279 of the study participants had died, a death rate that is 7 times higher than would be expected in the general population.
When the researchers broke the mortality rate down by the time of diagnosis, they found that those diagnosed later had a much improved mortality rate. The group diagnosed in the 1960s had a 9.3 times higher mortality rate than the general population, while the early 1970s group had a 7.5 times higher mortality than the general population. For the late 1970s group, mortality had dropped to 5.6 times higher than the general population.
The mortality rate in women with type 1 diabetes remained significantly higher, however, at 13 times the rate expected in women in the general population.
In addition, blacks with diabetes had a significantly lower 30-year survival rate than their white counterparts -- 57 percent versus 83 percent, according to the study.
Although Orchard said it isn't clear why women and blacks have higher-than-expected mortality, Barbara Araneo, director of complications therapies at the Juvenile Diabetes Research Foundation, said that both discrepancies have been found in other research, and that one theory is that blacks may have a greater genetic susceptibility to heart disease or high blood pressure. And, for women, she said previous research has shown that, "women with diabetes lose their innate protection against [heart disease], similar to the loss sustained in postmenopausal phases of life." But, she said, it's not clear how diabetes causes this loss.
The overall message of the study, however, is a positive one.
"The outcome of this study shows that diabetes care has improved in many ways over the last couple of decades, and as a result people with diabetes are living longer now," said Araneo, adding, "Managing and taking good care of your diabetes is the surest way to reduce the risk of developing complications later in life."
"What we're seeing now is incredibly encouraging, but it's not necessarily the full story yet," said Orchard, who noted that improvements in diabetes care should continue to lower mortality rates in people with type 1 diabetes.
Learn more about type 1 diabetes from the American Diabetes Association.