Type 2 diabetes the most common type in the United States is associated with obesity and increased risk of heart, kidney (renal) and eye complications. Meanwhile, heart attacks (myocardial infarctions or MI) are the most common cause of death in persons with the disease.
Now, a new study of records of over two million Swedish people has linked the excess risk of death from any cause, and from cardiovascular (CVD) causes, to the level of control of blood glucose as well as to the level of kidney complications.
Dr. Mauro Tancredi from the University of Gothenburg in Gothenburg, Sweden, and colleagues from several institutions, examined the records of the Swedish National Diabetes Register for people with at least one entry between 1998 and 2011. Each person with diabetes was matched with five non-diabetic individuals (controls) of the same gender, age, and county of birth. Thus records of 435,000 patients and 2.1 million controls were included in the study.
Over all, risk of death from any cause was 27 percent greater in diabetic persons than in controls; death from CVD causes was 33 percent greater for those with diabetes than for controls. Further, these risks were greater for younger (less than 55-years old) than for older diabetic patients.
When the researchers analyzed the interaction between deaths and first, control of blood glucose and kidney complications, they found that both influenced the risk of death. Patients under 55 old who had reasonably well controlled blood glucose levels (glycated hemoglobin less than 6.9 percent), still had around twice the risk of death from all causes as well as from CVD causes compared to controls.
When glucose control was poor (glycated hemoglobin greater than 9.7 percent), the risk of death for patients under 55 was much higher over four times greater compared to controls for death from any cause, and more than five times greater for cardiovascular causes.
Similarly, even when kidney function was normal (low amount of protein in the urine), the risk of death from all causes was nearly twice that of controls, and from CVD a little over twice the risk in controls. But diabetic patients over 65-years old with normal kidney function had a lower risk than controls of death from any cause and from CVD. When kidney function was poorest, the risk of death from any cause ranges from nearly 15 times greater than controls for the under-55 group, to three-fold greater in the oldest patients.
The authors concluded "excess mortality in Type 2 diabetes was substantially higher with worsening glycemic control, severe renal complications, impaired renal function, and younger age."
They also noted that more diabetic patients were smokers and/or obese than the controls. Because of the higher risk seen in younger patients, even those with good glucose control and normal kidney function, the authors observed, "[s]moking cessation, increased physical activity, and the development of new cardiovascular-protective drugs, such as alternative lipid-lowering medications for persons who cannot take statins, may further improve outcomes in younger patients."