Excess all-cause mortality and cardiovascular mortality dropped substantially among adults with diabetes between 1997 and 2006, according to a report in Diabetes Care.
Data from the National Health Interview Surveys linked to the National Death Index on a nationally representative sample of 242,383 adults aged 18 years and older with and without diabetes (approximately 30,000 per year) demonstrated a 40% reduction in excess all-cause mortality and a 23% drop in excess cardiovascular disease (CVD) mortality among those with diabetes. These rates of improvement have exceeded those of the nondiabetic population, resulting in more than a 50% reduction in the excess death rates that have been repeatedly attributed to diabetes, Edward W. Gregg, Ph.D., and his associates said (Diabetes Care 2012;35:1252–7 [doi: 10.2337/dc11-1162]).
"These encouraging findings, however, suggest that diabetes prevalence is likely to rise in the future if diabetes incidence is not curtailed," said Dr. Gregg, who is from the Division of Diabetes Translation, Centers for Disease Control and Prevention, and his associates, two of whom are with the National Institute of Diabetes and Digestive and Kidney Diseases.
Among the population with diabetes, there were consistent increases over time in the levels of education, income, and obesity, as well as decreases in the proportion of smokers and those with sedentary behavior and difficulty walking. There were no significant changes in age, race/ethnicity, history of CVD, or diabetes duration. Most of those demographic trends over time were similar for the nondiabetic population.
From 1997-1998 to 2003-2004, 3-year CVD death rates declined among those diagnosed with diabetes by 4 deaths/1,000 person-years, from 9.5 to 5.6. In multivariate analyses adjusting for age, sex, race/ethnicity, and diabetes duration, diabetic adults in the most recent sample (2003-2004) had 40% lower CVD mortality (hazard rate ratio, 0.60) and 23% lower all-cause mortality (0.77) than did those individuals in the earliest sample (1997-1998). There were no significant changes in the rates of cancer mortality in persons either with or without diabetes, Dr. Gregg and his associates noted.
Deaths due to CVD also dropped in the nondiabetic population during that time, but to a lesser degree than in the diabetic population, from 3.7 to 3.3 deaths/1,000. Furthermore, there was not a significant decline in all-cause mortality among those without diabetes. As a result, both excess CVD and all-cause death rates associated with diabetes – as compared to those without diabetes – declined significantly (by 3.5 and 4.7 deaths/1,000 person-years, respectively).
All-cause and CVD death rates in the diabetic population declined among both men and women, although there was a slightly greater magnitude of decline in men than in women. Again, the trends for both men and women paralleled less dramatic reductions in the nondiabetic population.
"Although excess mortality risk remains high – about 2 deaths per 1,000 due to CVD and about 6 all-cause deaths – this excess risk is now considerably lower than previous reports and consistent with improvements in several risk factors, complications, and indicators of medical care and representative of gradual, ongoing improvement in health for people with diagnosed diabetes," Dr. Gregg and his associates wrote.
However, they pointed out, models have indicated that declining mortality among people with diabetes is expected to lead to a substantial increase in the prevalence of people living with the condition. "Thus, the excess mortality associated with diabetes, though declining, will be spread among a considerably greater proportion of the population. Ultimately, this means that the need for vigilant efforts to prevent vascular and neuropathic complication and early mortality associated with diabetes, along with efforts to reduce diabetes incidence, will continue to be major demands into the future."
No potential relevant conflicts of interest were reported.