As a physician, I often consider how to measure success for treating patients with diabetes. Keeping blood sugar lower with the use of medications — a top focus of most doctors — is critical. But a better, broader goal is to prevent complications, using every possible strategy. Diabetes itself has few symptoms, but its consequences can lead to disability and death.
To get a better understanding of the problems caused by diabetes, let’s meet Mrs. R., a 70-year-old woman in my Stanford clinic. I've changed some details to protect her privacy.
Mrs. R was diagnosed with Type 2 diabetes when she was 57. At that time, her fasting blood sugar level was 267 mg/dL (normal is less than 90) and her hemoglobin A1c (a measurement of long-term blood sugar levels) was 12.2 percent, more than double a normal value of less than 5.5. Her diabetes was already causing problems with chest pain from heart disease, foot ulcers and was contributing to her depression. She didn’t get along with her doctors at the time and had difficulties managing her diabetes treatment, which led her to develop several complications. It has been a long road to getting her diabetes under control over the past 13 years.
Complications develop because diabetes and its high blood sugar levels lead to a breakdown of multiple body systems that usually maintain a healthy energy balance. Among other problems, this breakdown creates inflammation throughout the body, especially in blood vessels.
We often think of blood vessels as passive pipes that deliver blood where it’s needed, but the lining of vessels is an active, living surface. High blood sugar levels affect this delicate lining just like sizzling cheese on a pizza burns the roof of your mouth. This damage caused by diabetes extends throughout the body.
A few of the complications include:
Heart and brain — By irritating blood vessels, diabetes accelerates damage caused by cholesterol blockages in the lining of arteries that bring oxygen and nutrients to all tissues in the body. In the arteries nourishing the heart, these cholesterol time bombs are more liable to burst open to cause a heart attack. This blockage of critical oxygen causes the death of heart muscle tissue. The same thing frequently occurs in the arteries that feed the brain. The resulting stroke kills off brain tissue. Unfortunately, lowering blood sugar is not be enough to prevent these difficulties. Some damage to arteries can't be reversed and diabetes causes injury in other ways beyond blood sugar.
Kidney — Diabetes damages kidney blood vessels as well as the filtration system that creates urine. This stresses and overworks the kidney, making kidney failure more likely. Diabetes is the most common reason for kidney dialysis, where a machine is needed to filter the blood after the kidneys fail.
Cognitive impairment – People with diabetes can have difficulties with thinking and memory. As people with diabetes age, diabetes causes a faster decline then normal in mental functioning. Researchers are still learning more about how diabetes affects the brain.
Depression and fatigue – Depression occurs twice as often in diabetes compared to other people. Fatigue is also a common difficulty. Both problems can occur soon after diagnosis and arise from high blood sugar levels and blood vessel inflammation as well as the stress and complexities of living with diabetes.
Nerves -- Damage to leg nerves (peripheral neuropathy) occurs because diabetes damages the small blood vessels that provide nutrition to these nerves, which die off, leaving numbness or pain instead of normal sensation.
Sexual dysfunction – Damage to key blood vessels as well as other diabetes complications frequently lead to sexual problems.
Eye -- Several forms of eye disease, many related to faulty blood vessels, make blindness a real threat in diabetes.
Stomach and intestines – In diabetes, the digestive system loses the ability to coordinate the passage of food from start to finish. This produces problems ranging from poor emptying of the stomach to constipation.
Skin – Foot ulcers are rare in healthy individuals, but common for those with diabetes. Loss of feeling in the feet from nerve damage makes injury more likely and then high blood sugar impairs healing. Problems with the feet and legs can require amputation.
Unfortunately, Mrs. R developed several additional complications of diabetes, including a toe amputation, early kidney disease, partial blindness and nerve damage, before fully managing her diabetes.
These serious complications indicate how seriously people with diabetes need to focus on treatment. But many less grave problems -- such as mild constipation -- can also seriously reduce quality of life. Everyone with diabetes or who is on the road to developing diabetes needs to know about these complications and the best strategies to prevent them.
This is the fourth in a series of blog posts discussing prediabetes and Type 2 diabetes. The first installments examined what happens inside the body in prediabetes, how to stop prediabetes from progressing and how doctors and patients can reframe their approach to diabetes. The next post will focus on treatments for diabetes that extend beyond medications to lower blood sugar.
Randall Stafford, MD, PhD, a professor of medicine and director of the Program on Prevention Outcomes and Practices, practices primary care internal medicine at Stanford. He is developing practical strategies to improve how physicians and consumers approach chronic disease treatment and prevention.
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