Extreme Heat and Hypoglycemia Risk in Older Insulin Users

TOPLINE:

Older adults (aged ≥ 65 years) with diabetes who received insulin may have an increased risk for serious hypoglycemic events in extreme heat.

METHODOLOGY:

• Thermoregulatory response is often compromised in older adults with diabetes, making them vulnerable to extreme heat.
• Researchers evaluated the association between ambient heat and risk for hypoglycemia in about 2 million and about 283,000 patients aged 65-100 years with diabetes from the United States and Taiwan, respectively, who received insulin.
• A serious hypoglycemic event was defined as a primary emergency department (ED) visit or an unplanned inpatient admission for hypoglycemia from June 1 to September 30.
• Medication use was determined by at least one prescription dispensing insulin within 90 days of the index event.
• The average heat index (HI), a combination of ambient temperature and humidity exposure, was calculated by zip code and grouped into percentiles: ≥ 99th, 95-98th, 85-94th, 76-84th, 25-74th, and < 25th.

TAKEAWAY:

• Among insulin users overall, 32,461 and 10,162 older adults from the United States and Taiwan, respectively, experienced a hypoglycemic event.
• The risk for a serious hypoglycemic event was about 40% higher among insulin users on days with an HI ≥ 99th percentile than 25-74th percentile (unadjusted odds ratio, 1.38; 95% CI, 1.28-1.48).
• Conversely, on days with a low HI (< 25th percentile), the risk for hypoglycemia among insulin users decreased.
• No substantial differences were observed in the risk for hypoglycemic events and HI by climate region in either country, such as between the US Northeast and Southwest.

IN PRACTICE:

SOURCE:

The study was conducted by first author Aayush Visaria, Department of Medicine, Rutgers Robert Wood Johnson Medical School, New Brunswick, New Jersey, and coauthors. The study was published online on December 7, 2023 in Diabetes Care.

LIMITATIONS:

• The individuals with hypoglycemia were older, were more frequently non-Hispanic Black in the United States, and had more comorbidities, so caution should be used before the results can be generalized to broader populations.
• The authors were unable to capture variables that can alter the risk for serious hypoglycemia, such as outdoor activity, exercise, and diet.
• Prescriptions may not reflect actual insulin use and adherence.

DISCLOSURES:

This study was funded by the US National Institutes of Health/National Institute on Aging. The authors declared no conflicts of interest.