Extreme Heat Events Raise Mortality Risk

WEDNESDAY, Dec. 3, 2025 (HealthDay News) — Extreme heat events (EHEs) are associated with higher mortality among California veterans with common cardiometabolic diseases, according to a study published online Nov. 25 in JAMA Network Open.

Evan Michael Shannon, M.D., from the University of California, Los Angeles, and colleagues investigated the association between EHEs and mortality among California veterans with common cardiometabolic diseases. The analysis included 13,556 veterans (Oct. 1, 2015, to Sept. 30, 2021) with a diagnosis of a cardiometabolic condition of hypertension, diabetes, ischemic heart disease, congestive heart failure, chronic kidney disease, stroke, or peripheral arterial disease identified from the Veterans Health Administration (VA) Corporate Data Warehouse.

The researchers found that EHEs were significantly associated with mortality at all percentile thresholds (e.g., at 95th percentile odds ratio [OR] range, 1.10 to 1.14). For veterans in high Area Deprivation Index (ADI) neighborhoods, the effect estimates were greater than for lower ADI neighborhoods (e.g., three-day EHEs at 95th percentile: OR, 1.44 [versus 1.12]). Similarly, mortality was higher for veterans who experienced homelessness versus those who did not (e.g., three-day EHEs at 95th percentile: OR, 1.25 [versus 1.12]). Findings persisted across EHE definitions. 

“Given the projected increase in EHEs as global mean temperatures increase, the VA and other integrated health care systems must develop heat preparedness and response plans to protect people from heat-related morbidity and mortality,” the authors write. 

Abstract/Full Text