People with type 1 diabetes may have a shorter life expectancy than their peers, but intensive treatment may help offset that risk, say two separate new studies.
In the first study, published in JAMA, Shona J. Livingstone of the University of Dundee in Scotland and her colleagues compared the life expectancy of Scottish men and women ages 20 and older who had type 1 diabetes to a group of adults without the condition.
Life expectancy after age 20 was an additional 46.2 years among men with type 1 diabetes, but 57.3 years among men without the condition, an estimated loss of 11.1 years.
The life expectancy after age 20 for women with type 1 diabetes was an additional 48.1 years, compared to 61 years among women without it, an estimated loss of 12.9 years for women with diabetes.
In the general population without type 1 diabetes, 76 percent of men and 83 percent of women lived to age 70, compared with 47 percent of men and 55 percent of women with type 1 diabetes.
The study also showed that even patients with type 1 diabetes who still had good kidney function had reduced life expectancy.
Dr. Helen Colhoun, a professor of public health at the University of Dundee and a co-author of the study, told Healthline that heart disease, heart attacks, and diabetic comas were responsible for the largest percentage of the estimated loss in life expectancy for patients younger than 50.
Colhoun said, “The data are good news for people with type 1 diabetes. They show much better average life expectancy than older reports from other countries. At the same time, they also show that further work needs to be done to get to a goal of no reduction in life span. These data emphasize that efforts to reduce both the acute complications of high and low blood sugar and also the chronic complications of diabetes need to be made.”
In an editorial commenting on the study, authors Dr. Michelle Katz and Dr. Lori Laffel, both from the Joslin Diabetes Center in Boston, said greater access to advanced diabetes technologies, education, and support from healthcare professionals is needed to close the life expectancy gap.
In a separate study, also published in JAMA, Dr. Trevor J. Orchard, a professor of epidemiology, medicine, and pediatrics at the University of Pittsburgh, looked at whether mortality differed between patients getting intensive vs. conventional therapy in the long-term follow-up of the Diabetes Control and Complications Trial (DCCT).
After an average of 27 years of follow-up for patients with type 1 diabetes, 6.5 years of initial intensive diabetes therapy was associated with a modestly lower rate of death from all causes, compared to conventional therapy.
The DCCT, which ran from 1983 to 1993, randomly assigned 1,441 volunteers with type 1 diabetes between the ages of 13 and 39 to intensive or conventional therapy. Volunteers were followed until December 31, 2012 in another study, called the Epidemiology of Diabetes Interventions and Complications.
Study participants were randomly assigned to receive either intensive therapy aimed at achieving blood sugar control as close to the nondiabetic range as safely possible, or conventional therapy with the goal of avoiding abnormally low or high blood sugar levels.
At the end of the DCCT, after an average of 6.5 years, intensive therapy was recommended to all participants and they returned to their doctors for care.
The overall risk of death in the intensive treatment group was lower than that in the conventional treatment group, although the absolute risk reduction was small — between 2 and 3 percent.
Cardiovascular disease, cancer, acute diabetes complications, and accidents or suicide were the primary causes of death. Higher levels of glycated hemoglobin, which is a common lab test that measures overall blood sugar control, were associated with all-cause mortality. The development of albuminuria, which is the presence of excessive protein in the urine, was also linked to a greater risk of death.
According to the study authors, intensive therapy is sometimes associated with increased low blood sugar levels, which in turn, can lead to increased mortality.
But, Orchard told Healthline, this study shows that “patients and healthcare providers can now fully adopt intensive therapy for type 1 diabetes without concern that it may lead to greater mortality risk, especially from hypoglycemia, or low blood sugar.”
Orchard said the study results are encouraging for people with type 1 diabetes. “The results show that intensive therapy is associated with low mortality, as well as a dramatically lower risk of complications. The final piece of the treatment puzzle is now in place,” said Orchard.