Extreme heat events are increasing in frequency and intensity and disproportionally affect older adults and individuals with chronic conditions.

Retrospective evaluation of a quality improvement initiative among care‑managed Medicare Advantage members of a U.S.-based payer randomly assigned to standard or enhanced outreach. Extreme heat forecasts were reviewed weekly to identify members in affected counties for outreach. Standard outreach involved routine nurse‑led telephonic care management. Enhanced outreach added brief heat‑specific education tailored to clinical risks. Outcomes included implementation measures and exploratory emergency department (ED) and inpatient admissions 30 days before and after heat‑triggered identification.

The cohort included 3,978 older adults (mean age: 75±9 y; 58% women) with high chronic disease burden. Standard care management outreach was delivered to 88.3% (3,514/3,978) of identified members, with no between-group differences (standard: 88.7% vs enhanced: 88.0%; P =0.53), demonstrating high fidelity. Engagement among outreached members was similar (standard: 86.5% vs enhanced: 86.7%; P =0.76). Heat-specific outreach was delivered to 17.3% of members assigned to enhanced outreach, with 79.5% engagement; limited crossover occurred in the standard group (2.9% outreached). ED visits and inpatient admissions declined modestly in both groups, with differences-in-difference estimates of -25 ED visits (95% confidence interval [CI]: -46 to 13; P =0.198) and -7 inpatient visits (95% CI: -44 to 46; P =0.84) per 1,000 members.

Heat‑responsive outreach was feasibly integrated into existing care management workflows while maintaining routine delivery and engagement. Future work should refine reach to evaluate clinical impact.