Hypoglycemia (low blood glucose) is one of the most dangerous potential risks of diabetes treatment, and can be a consequence of taking insulin or certain other diabetes drugs. Not only can hypoglycemia be immediately dangerous — possibly leading to loss of consciousness and even death — but studies show that over time, frequent episodes of hypoglycemia are associated with worse health outcomes in people with diabetes.
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So it seems reasonable to assume that when episodes of hypoglycemia and deaths increase at the same time — as has been the case recently in people with type 2 diabetes in the United States and other countries — hypoglycemia is probably what leads to those deaths. A new analysis shows, though, that this isn’t the case.
Hypoglycemia linked to deaths, but no causation
While it’s absolutely true that hypoglycemia is becoming more common in people with type 2 diabetes, an article published in the journal Diabetologia suggests that instead of leading to more deaths, this uptick in hypoglycemia is simply a result of other factors driving higher mortality.
Most of the recent increase in death among people with type 2 diabetes, the authors explain, is due to cardiovascular causes, along with cancer and other causes. Based on what’s currently known about hypoglycemia, it’s reasonable to assume that it could increase the risk of death from cardiovascular causes, but not from cancer or certain other causes.
So the researchers set out to discover how episodes of severe hypoglycemia affected the risk of death from various causes.
The researchers looked at a group of over 74,000 people diagnosed with type 2 diabetes between 1998 and 2010. This UK database tracked hospital admissions due to severe hypoglycemia, and also recorded the date and cause of all deaths within the group. The researchers used this data to identify the five-year risk of death from several specific causes, both in people admitted to the hospital for hypoglycemia and in those who didn’t have severe hypoglycemia.
During the study’s follow-up period averaging just over seven years, 388 people from the group were admitted to a hospital for severe hypoglycemia at least once. During this period, 236 of those people died, representing 61% of those hospitalized for hypoglycemia. In contrast, only 25% of participants without a history of severe hypoglycemia died during the follow-up period.
The researchers found that non-cardiovascular causes accounted for 71% of deaths — a number that was identical both in people hospitalized for hypoglycemia, and in those who weren’t. In a 60-year-old with at least one episode of severe hypoglycemia, the five-year risk of death after controlling for a number of factors (including blood pressure and cholesterol levels, HbA1c, and BMI) was 4.7% higher for cardiovascular causes, 1.4% lower for cancer, and 11.1% higher for other causes.
If hypoglycemia were driving the higher risk of death seen in people hospitalized for this condition, you would expect to see a bigger increase in the risk of death from cardiovascular causes, compared with other causes of death. Instead, there was a bigger increase in the risk of death from non-cardiovascular causes, after adjusting for factors that could skew the results.
Overall, the researchers concluded that severe hypoglycemia didn’t appear to be what drove the higher risk of death among people hospitalized for it. Instead, it appeared that hypoglycemia was mostly just a result of factors that led to an increased risk of death.
Hypoglycemia still an indicator of higher death risk
While this study suggests that hypoglycemia isn’t directly responsible for a higher risk of death in people with type 2 diabetes, it doesn’t show that hypoglycemia is nothing to worry about. On the contrary, it shows that being hospitalized for hypoglycemia means that you’re dramatically more likely to die in the next five years than someone who isn’t hospitalized for hypoglycemia.
So even if hypoglycemia isn’t directly leading to death, it’s still a sign that your health isn’t good, and that you should take steps to address factors that increase your risk of death when you have diabetes. These factors may include your overall blood glucose control, body weight, blood pressure, and cholesterol levels.
If you experience severe hypoglycemia, talk to your doctor both about ways to reduce your risk of future episodes of low blood glucose, and about ways to improve your overall health and diabetes control.
Want to learn more about hypoglycemia? Read “Understanding Hypoglycemia,” “What Is Hypoglycemia?: Symptoms and Treatments” and “Hypoglycemia: What Your Inner Circle Needs to Know.”
