TUESDAY, March 24, 2026 (HealthDay News) -- Health care systems can leverage electronic health record data to optimize health-based heat warning interventions, according to a study published online March 20 in JAMA Network Open.Evan Siau, M.D., from the New York University Grossman School of Medicine in New York City, and colleagues examined the associations between extreme heat exposure and all-cause ED visits among patients aged 65 years and older. Patients seeking emergency care during the summer (May 1 to Sept. 30) from 2022 to 2024 at two New York City EDs were included: ED-1, which mainly served Medicaid-enrolled patients from minoritized racial and ethnic groups, and ED-2, which mainly served White, privately insured patients.The study included 55,200 ED encounters, representing 15,092 unique patients at ED-1 and 19,559 at ED-2. The researchers found that daily maximum heat index (HImax) associations increased after 66 degrees Fahrenheit (odds ratio, 1.10) at ED-1, peaking at 101 degrees Fahrenheit (odds ratio, 1.24), and were higher on days with HImax anomalies between 15 and 18 degrees Fahrenheit warmer than average (odds ratios, 1.07 and 1.10, respectively). Daily HImax ED use associations were not significant at ED-2 and were significantly negative for days with HImax anomalies above 16 degrees Fahrenheit, with a nadir at 21 degrees Fahrenheit warmer than average (odds ratio, 0.84)."Our hope is that other health care systems will leverage their own electronic health record data to identify the heat thresholds at which their patients are most at risk and target interventions appropriately," senior author Alexander Azan, M.D., also from the Grossman School of Medicine, said in a statement.One author disclosed ties to Ambu Consulting and Philips.Abstract/Full Text.Sign up for our weekly HealthDay newsletter