STOCKHOLM – Having diabetes doubles the risk for death from a multitude of causes and shortens the life span by 5-7 years, judging from evidence from the United Kingdom Prospective Studies Collaboration presented at the annual meeting of the European Association for the Study of Diabetes.
Patients with diabetes were two and a half times more likely than those without it to die from ischemic heart disease (odds ratio, 2.37; 95% confidence interval, 2.23-2.52). They were also more likely to die from ischemic stroke (OR, 2.75; 95% CI, 2.29-3.31) and “a surprising association with” cardiac arrhythmia (OR, 2.47; 95% CI, 1.80-3.38) was found, said the presenting author, Dr. Louisa Gnatiuc of the clinical trial service unit and epidemiological studies unit at Oxford (England) University. She noted, however, that diabetes was more weakly associated with death from nonischemic causes (OR, 1.57; 95% CI, 1.34-1.85).
In addition, diabetic individuals were almost twice as likely as those with no diabetes to die from renal (OR, 1.90; 95% CI, 1.40-2.58) or hepatic (OR, 1.75; 95% CI, 1.36-2.26) causes, and there was a 13% increase in the overall risk for death from cancer (OR, 1.13; 95% CI, 1.06-1.21). The small increased risk for cancer death was largely due to deaths from oral (OR, 1.81; 95% CI, 1.17-2.81), liver (OR, 1.80; 95% CI, 1.26-2.58), and pancreatic (OR, 1.57; 95% CI, 1.21-2.03) cancers, Dr. Gnatiuc observed. Diabetic individuals were also more likely to die from respiratory causes than their nondiabetic counterparts (OR, 1.59; 95% CI, 1.37-1.83).
These data provide further insight into the risk for death from a multitude of causes in patients with diabetes, said Dr. Naveed Sattar, who was not involved in the analysis, in an interview. “While it is pretty much a replication of the Emerging Risk Factor Paper that was published in the New England Journal of Medicine, there is a little bit of new information here, such as the relative risks in women versus men and by age as well,” he observed.
The odds ratio for death from ischemic heart disease was higher among women aged 35-39 years with diabetes versus those with no diabetes than in men aged 35-39 years with diabetes versus no diabetes, at 5.61 (95% CI, 4.08-7.72) and 2.49 (95% CI, 2.16-2.85), respectively. Similar finding were seen at other age ranges, with around a twofold increase in men aged 60-69 years (OR, 2.26; 95% CI, 2.01-2.53) and 70-89 years (OR, 1.89; 95% CI, 1.70-2.11), but a two- to fourfold increase in women aged 60-69 years (OR, 4.15; 95% CI, 3.38-5.10) and 70-79 years (OR, 2.45, 95% CI, 2.11-2.84).
“So it looks like if you develop diabetes younger, your risk for mortality’s higher,” said Dr. Sattar, professor of metabolic medicine at the Institute of Cardiovascular and Medical Sciences, University of Glasgow (Scotland). “That makes sense,” he added, “because if you develop type 2 diabetes at the age of 30, it must be a much more malignant type of diabetes than, say, if you developed diabetes at age 80, and there are other data that now confirm that is the case as well.”
The analysis was based on data from 44 prospective studies that recorded 55,855 deaths in 690,700 adults who had no prior vascular or other chronic diseases at baseline. Men accounted for 60% of the study population, with a mean age of 48 years. During the postpresentation discussion, Dr. Gnatiuc noted that it was difficult to standardize the definition of diabetes used in the study and that all 25,000 cases of diabetes included in the study had been self-reported. It is likely that most cases were type 2. No information on the duration of diabetes was available, but she noted that this should not matter given the prospective nature of the analysis.
During 13 million patient-years of follow up the most common cause of death was ischemic heart disease, accounting for 17,218 deaths, followed by cancer (18,658 deaths). There were 5,466 strokes of which 1,353 were ischemic (OR, 2.75; 95% CI 2.29-3.31), 1,124 hemorrhagic (OR, 1.59; 95% CI 1.26-2.01), 2,563 that were unspecified (OR, 2.30; 95% CI 1.99-2.66), and 626 classed as subarachnoid hemorrhage (OR, 0.62; 95% CI, 0.36-1.08). Vascular causes of death included inflammatory heart disease, sudden death, and atherosclerosis, among others, which were all increased in diabetic versus nondiabetic subjects.
Dr. Gnatiuc noted that the risk for ischemic heart disease increased with increasing age, systolic blood pressure, and total cholesterol in diabetics and in nondiabetics, although it was much higher in those with diabetes than in those without. “Controlling blood pressure, cholesterol, and obesity are particularly important to reduce absolute mortality rates in those with diabetes, she suggested.