The danger of diabetes is not only the immediate risk of very high blood sugar. Diabetes also has many dreaded long-term complications. (In this post I am referring to both type 1 and type 2 diabetes mellitus.) Diabetes greatly increases the risk of stroke, heart attack, and amputation. In the US it is the leading cause of kidney failure and of blindness in adults.
A study performed by researchers at the Centers for Disease Control and Prevention and published in the New England Journal of Medicine tracked the frequency in the US of five serious complications of diabetes over the two decades from 1990 to 2010. This was not an experiment in which a medication or diagnostic test is evaluated. This was simply counting how many people had diabetes in the US, and how many of them suffered heart attacks, strokes, kidney failure, amputations, or death due to very high blood sugar.
The results were very encouraging. The rate of heart attacks among diabetics fell by two thirds, as did the rate of death due to very high blood sugar. This parallels a similar but smaller drop in the frequency of heart attacks in the general population. Stroke and amputation rates both declined by about half. The risk of permanent kidney failure declined by about a quarter.
What accounts for these favorable trends? Part of the credit lies with earlier detection and better treatment of diabetes. Screening for early complications of diabetes by checking for early signs of kidney injury and for the first signs of skin sores helps prevent amputations and kidney failure.
But much of the credit for these positive trends has nothing to do with diabetes, but with general improvements in preventing cardiovascular disease. Fewer people are smoking. Statins have revolutionized treatment for high cholesterol and have drastically reduced the incidence of strokes and heart attacks in the general populations. Improved use of blood pressure medications have also contributed to stroke and heart attack prevention and have prevented kidney failure. And all of these measures have helped reduce the frequency of amputations.
So as cardiovascular risks have declined in the general population, people with diabetes who are at very high risk have benefited most. That’s great news.
The one bit of data in the study that is terrible news is that from 1990 to 2010 the number of people with diabetes in the US grew from 6.5 million to 20.7 million. So the frequency of terrible complications from diabetes is declining, but the number of people subject to these complications has more than tripled. This is terrific news for the individual with diabetes. Diabetes has never been less scary or more manageable. But for the society as a whole, the news is mixed.
To make further progress in decreasing complications from diabetes we must figure out how to stem the tide of the diabetes epidemic. For type 2 diabetes this may mean earlier detection of risk factors and expanded use of weight loss surgery for appropriate patients. It may also mean working to reverse the epidemic of obesity — a quixotic task. For type 1 diabetes this may mean further work on an artificial pancreas and on immunotherapy that might arrest the disease in its very early stages when some pancreatic function remains.
We’ve come a long way. We’ve got a long way to go.
Albert Fuchs is an internal medicine physician who blogs at his self-titled site, Albert Fuchs, MD.