From 65 years old, people with diabetes and insulin treated may have an increased risk of serious hypoglycemia in the event of extreme heat, according to a study published last year in Diabetes Care .
The thermoregulating response is often compromised in elderly people with diabetes, making them vulnerable to extreme heat.
Researchers have evaluated the link between ambient heat and the risk of hypoglycemia in approximately 2 million people with diabetes in the United States and around 283,000 diabetic patients in Taiwan. All patients, aged 65 to 100, received insulin.
A serious hypoglycemic episode was defined as an emergency visit or hospitalization for hypoglycemia between June 1 and September 30.
Taking medication was determined by at least one insulin prescription issued within 90 days of the index event.
The average heat index, which combines ambient temperature and exposure to humidity, has been calculated by postal code and grouped into percentiles: ≥ 99th, 95-98e, 85-94e, 76-84e, 25-74e and <25e.
It appears from data that among all insulin users, 32,461 elderly people in the United States and 10,162 in Taiwan suffered a hypoglycemic episode, respectively.
The risk of severe hypoglycemic episode was around 40 % higher in insulin users on days when the average heat index was ≥ 99th percentile that the days when it was between the 25th and 74th percentile (non-adjusted dimension ratio, 1.38; 95 % CI, 1.28-1.48).
Conversely, the days when the heat index was low (<25th percentile), the risk of hypoglycemia in insulin users decreased.
No significant difference was observed concerning the risk of hypoglycemic episodes and the heat index according to the region in the two countries, for example between the northeast and the southwest of the United States.
“Our observation of an increased risk of emergency visits linked to hypoglycemia in the elderly using insulin and exposed to extreme heat highlights the need for patients and health professionals to be aware and cautious about the fact that extreme heat can increase the risk of hypoglycemia”, conclude the authors.
However, they underline some limits to their study. People with hypoglycemia were older, were more often non-Hispanic blacks in the United States and presented more comorbidities. It is therefore advisable to be cautious before generalizing the results to wider populations.
Also, researchers could not have information on certain variables likely to modify the risk of severe hypoglycemia, such as outdoor activities, physical exercise and food.
Finally, prescriptions may not reflect the real use of insulin and the observance of treatment.
This study was funded by the National Institutes of Health/National Institute on Ater in the United States. The authors said they had no conflict of interest.
This article was initially published on Medscape.com.
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