Broadly speaking, type 1 diabetes harms health in two ways: high blood sugar and low blood sugar. Unhealthy blood sugar levels can cause fatal situations to develop slowly over a period of years or decades, or quickly, within minutes.
Hyperglycemia: Long-Term Risks
Hyperglycemia (high blood sugar) is the root cause of most of the long-term complications of diabetes and is the most significant contributor to reduced life expectancy. Persistently high blood sugars harm the heart and blood vessels, the nerves, vital organs such as the kidneys, and many other parts of the body.
Cardiovascular disease is the leading cause of death in people with type 1 diabetes. While many adults without diabetes eventually die of cardiovascular disease (heart disease is the most common cause of death in the United States), people with type 1 diabetes usually experience heart disease about one decade earlier. The higher your blood sugar levels are above normal, as measured by A1C, the greater your risk of early death from cardiovascular disease.
Kidney disease is a second major cause of early death in people with type 1 diabetes. The development of kidney problems is a direct consequence of hyperglycemia; elevated blood sugar levels are the strongest predictor of chronic kidney disease in people with type 1 diabetes.
Hyperglycemia: Short-Term Risks
In the short term, the chief danger of high blood sugars is the development of diabetic ketoacidosis (DKA). In DKA, a critical lack of insulin causes the blood to become acidic and toxic. If not treated at a hospital, it can be deadly. Many people are only diagnosed with type 1 diabetes after developing DKA.
This dangerous condition is less likely to occur in people who have already been prescribed insulin. Nevertheless, DKA remains a significant risk for people with long-standing type 1 diabetes. The condition, which ultimately always stems from an insufficient amount of insulin, can also be precipitated by rationing or skipping insulin doses, dehydrating illnesses (such as the stomach flu), heart attacks, and insulin delivery malfunctions (such as insulin pump tubing problems).
Hypoglycemia
Hypoglycemia (low blood sugar), an omnipresent risk in people who use insulin, can cause death quickly. Severe low blood sugar levels can cause people to pass out, sometimes leading to coma or death. Hypoglycemia can also precipitate death indirectly by causing car crashes, drowning, falls, and other accidents. Repeated bouts of hypoglycemia also lead to a condition called “hypoglycemia unawareness,” in which people fail to experience the usual symptoms and warning signs of low blood sugar, increasing the risk. Guarding against severe low blood sugars is one of the most important lessons to learn about life with type 1 diabetes.
Historical data has suggested that as many as 4 to 10 percent of patients with type 1 diabetes have died during hypoglycemic episodes. But it’s possible that the rate of death has improved significantly in recent years. The development of the continuous glucose monitor (CGM), in particular, has given many people the ability to track their blood sugar levels continuously, reducing the likelihood of being surprised by severe hypoglycemia. CGMs can sound alarms when glucose levels are trending down toward dangerous territory, alerting users of the need to intervene.
