People with type 1 diabetes lose more than a decade of life to the chronic disease, despite improved treatment of the illness and its complications – a new Scottish study reports.
But, second study suggests that intensive blood sugar management can make a difference.
Men with type 1 diabetes lose about 11 years of life expectancy compared to men without the disease.
And, women with type 1 diabetes have their lives cut short by about 13 years, according to a report published in the Journal of the American Medical Association.
The findings "provide a more up-to-date quantification of how much type 1 diabetes cuts your life span now, in our contemporary era," said senior author Dr. Helen Colhoun, a clinical professor in the diabetes epidemiology unit of the University of Dundee School of Medicine in Scotland.
Read: Treating type 1 diabetes
Impact on heart health
Diabetes' impact on heart health appeared to be the largest single cause of lost years, according to the study. But, the researchers also found that type 1 diabetics younger than 50 are dying in large numbers from conditions caused by issues in management of the disease – diabetic coma caused by critically low blood sugar, and ketoacidosis caused by a lack of insulin in the body.
"These conditions really reflect the day-to-day challenge that people with type 1 diabetes continue to face, how to get the right amount of insulin delivered at the right time to deal with your blood sugar levels," Colhoun said.
A second study, also in JAMA, suggested that some of these early deaths might be avoided with intensive blood sugar management.
In that paper, researchers reduced patients' overall risk of premature death by about a third, compared with diabetics receiving standard care, by conducting multiple blood glucose tests throughout the day and constantly adjusting insulin levels to hit very specific blood sugar levels.
"Across the board, individuals who had better glucose control due to intensive therapy had increased survival," said co-author Dr. Samuel Dagogo-Jack, chief of the division of endocrinology, diabetes and metabolism at the University of Tennessee Health Science Centre in Memphis.
Tight control of blood glucose important
Strict control of blood sugar appears to be key.
Researchers observed a 44 percent reduction in overall risk of death for every 10 percent reduction in a patient's haemoglobin A1c, a test used to determine a person's average blood sugar levels over the prior three months, Dagogo-Jack said.
The Scottish study looked at the life expectancy of nearly 25,000 people with type 1 diabetes in Scotland between 2008 and 2010. All were 20 or older. There were just over 1,000 deaths in this group.
The researchers compared the people with type 1 diabetes to people without the chronic disease. Researchers used a large national registry to find and analyse these patients.
The investigators found that men with type 1 diabetes had an average life expectancy of about 66 years, compared with 77 years among men without it. Women with type 1 diabetes had an average life expectancy of about 68 years, compared with 81 years for those without the disease, the study found.
Heart disease accounted for the most lost life expectancy among type 1 diabetics, affecting 36 percent of men and 31 percent of women.
Diabetes damages the heart and blood vessels in many ways, mainly by promoting high blood pressure and hardening of the arteries, Colhoun said.
Read: How diabetes affects the heart
Ketoacidosis another leading cause of death
However, those younger than 50 appeared to die most often from diabetes management complications.
In men, about 29 percent of life expectancy lost for people under 50 was due to diabetes management-related complications like diabetic coma or ketoacidosis, a condition in which the body suffers from high levels of poisonous acids called ketones.
These ketones are created when the body burns fat for energy, because low insulin levels are preventing the conversion of blood sugar into fuel. In women under 50, that number was 22 percent, according to the study.
Intensive treatment of their diabetes might have extended these lives, Dagogo-Jack suggested.
In his study, more than 1,400 people with type 1 diabetes were randomly assigned to either receive intensive management of their diabetes or normal therapy.
People who got intensive therapy kept near-constant tabs on their blood sugar levels, and made quick adjustments to their insulin therapy to keep their blood sugar as close to normal as safely possible, the study reported.
The intensive therapy lasted an average of 6.5 years, through the mid-1980s and 1990s. Afterward, patients were taught how to conduct their own intensive management and urged to continue using those techniques. Doctors then tracked their health and progress through the end of 2012.
After an average 27 years of follow-up, the researchers found that the odds of dying were nearly one-third lower for the intensive management group who kept their blood sugar tightly controlled.
Read: Poverty makes diabetes management more difficult
Diabetes management more achievable
Such intensive diabetes management is now more achievable than it was back in the 1980s, when the study began, said Dr. Ned Kennedy, chair of endocrinology for the Cleveland Clinic.
"Time has moved on and technology has moved on considerably," Kennedy said. "Many patients now have access to real-time multiple glucose measurements during the day, either by doing finger stick measurements or using continuous glucose monitoring," he explained.
"The real exciting developments are, we are getting to the stage where we can marry up the information from continuous glucose monitoring to the delivery of insulin through insulin pumps," Kennedy continued.
"This technology will make it easier for large numbers of patients to reach the level of glucose control that these patients achieved."
As far as the ongoing loss of life expectancy to type 1 diabetes, both Colhoun and Dagogo-Jack said that the Scottish findings can be looked at as positive.
People in the 1920s diagnosed with type 1 diabetes had a life expectancy "on the order of months, clearly less than one year," Dagogo-Jack said.
Read: Technology lightens the burden of diabetes
On the right track
The discovery of insulin improved things somewhat, but it wasn't until the 1980s that medicine figured out how to best use insulin to control blood sugar levels.
"It looks as though we are on the right track," Colhoun said. "Outcomes are improving, and I expect they will continue to improve, but we are by no means there yet."
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