DOI: 10.2337/dc23-1189 ISSN: 0149-5992

Ambient Heat and Risk of Serious Hypoglycemia in Older Adults With Diabetes Using Insulin in the U.S. and Taiwan: A Cross-National Case-Crossover Study

Aayush Visaria, Shu-Ping Huang, Chien-Chou Su, David Robinson, John Read, Chuan-Yao Lin, Rachel Nethery, Kevin Josey, Poonam Gandhi, Benjamin Bates, Melanie Rua, Ashwagosha Parthasarathi, Arnab K. Ghosh, Yea-Huei Kao Yang, Soko Setoguchi
  • Advanced and Specialized Nursing
  • Endocrinology, Diabetes and Metabolism
  • Internal Medicine


To measure the association between ambient heat and hypoglycemia-related emergency department visit or hospitalization in insulin users.


We identified cases of serious hypoglycemia among adults using insulin aged ≥65 in the U.S. (via Medicare Part A/B/D-eligible beneficiaries) and Taiwan (via National Health Insurance Database) from June to September, 2016–2019. We then estimated odds of hypoglycemia by heat index (HI) percentile categories using conditional logistic regression with a time-stratified case-crossover design.


Among ∼2 million insulin users in the U.S. (32,461 hypoglycemia case subjects), odds ratios of hypoglycemia for HI >99th, 95–98th, 85–94th, and 75–84th percentiles compared with the 25–74th percentile were 1.38 (95% CI, 1.28–1.48), 1.14 (1.08–1.20), 1.12 (1.08–1.17), and 1.09 (1.04–1.13) respectively. Overall patterns of associations were similar for insulin users in the Taiwan sample (∼283,000 insulin users, 10,162 hypoglycemia case subjects).


In two national samples of older insulin users, higher ambient temperature was associated with increased hypoglycemia risk.

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