Mortality rates among U.S. adults decreased in recent years, and the rate of decline was greater in those with diabetes than those without diabetes, a recent study found.
CDC researchers estimated mortality trends by using data from National Health Interview Survey Linked Mortality Files between 1985 and 2015. They assessed proportional mortality from all causes, vascular causes, cancer, and nonvascular/noncancer causes, as well as age-specific death rates among adults with and without diabetes. Results were published online on May 18 by The Lancet.
Between 1988 to 1994 and 2010 to 2015, all-cause mortality rates among U.S. adults with diabetes decreased by 20% every 10 years, from 23.1 (95% CI, 20.1 to 26.0) to 15.2 (95% CI, 14.6 to 15.8) per 1,000 person-years. Rates of death per 1,000 person-years from vascular causes decreased by 32% every 10 years, from 11.0 (95% CI, 9.2 to 12.2) to 5.2 (95% CI, 4.8 to 5.6), while rates of death from cancer decreased by 16% every 10 years, from 4.4 (95% CI, 3.2 to 5.5) to 3.0 (95% CI, 2.8 to 3.3). The rate of nonvascular/noncancer deaths per 1,000 person-years decreased by 8% every 10 years, from 7.7 (95% CI, 6.3 to 9.2) to 7.1 (95% CI, 6.6 to 7.5).
Declines in mortality rates were also significant among people without diabetes for all four categories. However, declines in death rates among people with diabetes were significantly greater for all causes (P<0.0001 for interaction), vascular causes (P=0.0214 for interaction), and nonvascular/noncancer causes (P<0.0001 for interaction) compared to those without diabetes.
Among adults with diabetes, the proportion of total deaths from vascular causes dropped from 47.8% (95% CI, 38.9% to 58.8%) in 1988 to 1994 to 34.1% (95% CI, 31.4% to 37.1%) in 2010 to 2015. During the same time period, the proportion of deaths from nonvascular/noncancer causes increased from 33.5% (95% CI, 26.7% to 42.1%) to 46.5% (95% CI, 43.3% to 50.0%). The proportion of deaths caused by cancer remained stable over time, ranging from 15.9% (95% CI, 12.9% to 19.6%) in 1995 to 1999 to 19.9% (95% CI, 18.1% to 22.0%) in 2010 to 2015.
All-cause mortality rates among adults with diabetes dropped most in men and those ages 65 to 74 years. There was no decline in death rates among people with diabetes ages 20 to 44 years.
The study authors noted limitations to their analyses, such as the possibility that cause-of-death reporting shifted over time or with the transition from ICD-9 to ICD-10. They added that diabetes was self-reported and that information on diabetes type was unavailable.
“The reduction in relative risk of all-cause and vascular-disease death associated with diabetes should not be interpreted as an indication that the public health burden of diabetes is declining,” the authors cautioned. “One byproduct of the reduction in mortality has been the increase in lifetime risk and years spent with diabetes in the USA.”
Based on the study data, the number of deaths per year in the U.S. that were attributable to diabetes changed slightly over time, from 112,240 deaths in 1995 to 1999 to 124,490 deaths in 2010 to 2014, an accompanying editorial noted.
“Thus, it is encouraging to see that the excess mortality attributable to diabetes has changed little over the past 20 years despite a tripling of the number of people with diabetes and provides reason for guarded optimism about diabetes treatment and control programmes,” the editorialist wrote.