Heat, Nurse Workload, and Patient Safety in Hot-Climate Hospitals: A Two-Month Time-Series Study (May–June 2025)

This study examined the relationship between environmental heat and hospital safety outcomes in hot-climate settings. Using a retrospective ecological time-series design, we analyzed data collected from May to June 2025 across multiple hospital units. Daily maximum heat index values were merged with nurse staffing rosters and patient safety incident logs. Nurse workload indicators included patients-per-nurse ratios, overtime minutes, and sick leave, while safety outcomes were captured as falls and medication errors per 1,000 patient-days.

Advanced time-series models, specifically quasi-Poisson regression with distributed lags, were employed to capture short-term effects of heat exposure while adjusting for potential confounders such as day-of-week, hospital site, and unit type.

Findings indicated that days with a heat index above 41 °C were associated with increased overtime, higher patient falls, and greater medication error rates. Mediation analyses further suggested that nurse workload partially explained the relationship between heat exposure and safety incidents.

This study highlights the vulnerability of healthcare systems to environmental stressors and underscores the need for climate-adaptive staffing strategies and protective policies to ensure nurse well-being and patient safety.