Mortality among adults with diabetes

By Arvind M. Dhople, Ph.D., Professor Emeritus, Florida Tech

                Diabetes is a chronic disease that occurs either when the pancreas does not produce enough insulin or when the body cannot effectively use the insulin it produces.  Insulin is a hormone that regulates blood sugar.  Hyperglycemia, or raised blood sugar, is a common effect of uncontrolled diabetes and over time leads to serious damage to many of the body’s systems, especially the nerves and blood vessels.                                                                                                                                                        

                Large reductions in diabetes complications have altered diabetes-related morbidity in the U.S.  It is unclear whether similar trends have occurred in causes of death.

                The Global Burden of Disease 2016 study reported diabetes to be the twelfth leading cause of disability globally and attributed nearly 1.5 million deaths to diabetes worldwide.  Other studies estimate that the number of people living with diabetes today range from 415 million to 425 million, with a projection of as many as 700 million people living with the disease by 2025.  Aging populations, increasing urbanization, and widening social inequalities are all contributing factors to the rapid rise in diabetes prevalence seen over the past 40 years.  It seems according to the United Nations (UN), reducing premature mortality from non-communicable diseases, including diabetes, has become a global priority.

                For people with either type 1 or type 2 diabetes, advances in clinical care, such as development of better glucose-lowering drugs and structural education programs, have led to considerable increases in life expectancy.  Effectively, more people are living with diabetes for longer.  Understanding the disease course, onset of complications, and comorbid conditions is critical to improving specialized care for people with diabetes.

                In the American Diabetes Association meeting in June 2019, Dr. Gregg had mentioned on trends in cause-specific mortality among adults with and without diagnosed diabetes in the U.S.  Using National Vital Statistics data, it showed a staggering five times of diagnosed cases of diabetes in U.S. from 6.2 million cases in the late 1980s to 34.2 million cases in December 2020 (or just one in ten have diabetes).

                Deaths attributable to cardiovascular disease for both men and women with and without diabetes declined significantly over the periods mentioned earlier.  Although still numerically higher, the rate of cardiovascular-associated deaths in people with diabetes declined far more rapidly than for those without diabetes.  Modest by comparison, but encouraging nonetheless, overall cancer-related mortality was also reduced, largely due to declines in deaths from breast and colorectal cancers, but deaths from pancreatic and liver cancers have increased.  In people with diabetes, deaths from other causes, such as unintentional injuries, lower respiratory tract disease, hypertension, infections, and renal disease, were all increased.

                These studies clearly demonstrate the complexity of the story underlying mortality in people with diabetes.  And the picture presented in the U.S. will most likely be reflected in other regions as the global epidemic marches on.  The diversity in causes of death signals and important call for clinical management and public health reform to better care for patients with diabetes.  Undoubtedly, reducing risk of cardiovascular disease is important, but increases in liver and renal disease and in deaths from sepsis and other infections cannot be ignored.  More research focused on the mechanisms driving the increase in unintentional injuries is urgently needed. 

                Understanding the genetic underpinning of diabetes pathogenesis and risk of developing complications has the potential to help shape clinical management at an individual patient level.  New technologies and data from large-scale genome projects have equipped researchers with powerful tools to better understand diabetes.

                People with diabetes are leading longer lives.  As mortality from cardiovascular complications continues to decline, attention must be turned to identifying, preventing, and treating other diabetes complications.  There is no scope for complacence in diabetes care.  Understanding and managing complications associated with the disease must become clinical and public health priority.