High Blood Sugar Raised Heart Disease Risk in Type 1 Diabetes

Improved blood sugar control in type 1 diabetes patients may decrease their risk of death from heart disease

(RxWiki News) For patients with type 1 diabetes, living life free of heart disease may be all about keeping blood sugar under control.

A new study found that patients with type 1 diabetes who had poor blood sugar control had a raised risk of dying from heart disease.

"The most interesting finding of the study is that patients who had type 1 diabetes and had good glycemic [blood sugar] control still had a two-fold increased risk of mortality from any cause or from cardiovascular causes than the general public," said David Wenkert, MD, PhD, Director of Endocrinology for Scott & White Memorial Hospital in Temple, TX. "However, those patients with poorer glycemic control had even further increased risk of death."

Controlling blood sugar control over time is key to decreasing the risk of heart disease in patients with diabetes. The authors of this study found that people with type 1 diabetes had a much higher risk of death from any cause — including heart disease — than the general population.

According to Dr. Wenkert, the main difficulties diabetes patients face when it comes to maintaining stable blood sugar include frequent monitoring of blood sugar levels, adjusting insulin doses and maintaining a good diet.

Marcus Lind, MD, PhD, chief of diabetology at Uddevalla Hospital in Trollhättan, Sweden, led the study. These researchers used the Swedish National Diabetes Register to collect data. The team collected data on 33,915 patients with type 1 diabetes and matched each patient with five similar but healthy patients without diabetes — the control population.

People with type 1 diabetes suddenly stop secreting insulin as children, adolescents or young adults. They must take insulin injections or use an insulin pump and carefully manage their diet and exercise to keep their blood sugar under control. Insulin is a hormone that regulates blood sugar.

This level of blood sugar control is measured with a blood test called the HbA1c. A person with type 1 diabetes should have an HbA1c of 7 percent or less, Dr. Lind and colleagues noted.

Patients in the study were 36 years old on average and had had type 1 diabetes for an average of 20 years. Fifty percent were men and 45 percent were women.

Dr. Lind and team found that only 13 to 15 percent of the patients with diabetes in the study had an HbA1c level that indicated good blood sugar control. Twenty percent of the patients had HbA1cs above 8.8 percent, indicating very poor control.

In both the group with diabetes and the control population, men were more likely to die during the study period. Heart disease was the most common cause of death for both sexes.

Between 1998 and 2011, 8 percent of the patients with type 1 diabetes died — compared to 2.9 percent of the control population. The risk of dying was 30 to 40 times higher for patients with type 1 diabetes who also had severe kidney disease.

Diabetes patients with an HbA1c of 6.9 percent or less still were twice as likely as the control group patients to die during the study — and three times more likely to die of heart disease. Those with an HbA1c of 9.7 percent or higher were 8.5 times more likely to die of heart disease than people without diabetes.

This study was published Nov. 20 in the New England Journal of Medicine.

This study was funded by the Swedish government, the Swedish Society of Medicine, the Swedish Heart and Lung Foundation and the Swedish Research Council, among others.

Several study authors reported conflicts of interest, primarily with companies that manufacture insulin or other diabetes-related products. Dr. Lind received fees from AstraZeneca and Novo Nordisk and grant support from AstraZeneca, Novo Nordisk, Pfizer, Abbott and DexCom. Study author Dr. Mikhail Kosiborod received fees for serving on advisory boards for AstraZeneca, Regeneron, Eli Lilly and Medtronic MiniMed. Study author Dr. Hans Wedel received fees for serving on steering committees for Roche.

Review Date: 
November 21, 2014