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

<p dir="ltr">Objective: To measure the association between ambient heat and hypoglycemia-related ED visit or hospitalization in insulin users.</p><p dir="ltr">Research Design and Methods: We identified cases of serious hypoglycemia among adults using insulin aged ≥65 in the US (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.</p><p dir="ltr">Results: Among ~2 million insulin users in the US (32,461 hypoglycemia cases), ORs for HI >99th, 95-98th, 85 94th, and 75-84th percentiles compared to 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 cases).</p><p dir="ltr">Conclusions: In two national samples of older insulin users, higher ambient temperature was associated with increased hypoglycemia risk.</p>