Long fever Fever as a long-term risk factor for mortality in persons in assisted living facilities

BACKGROUND: The aging population and increasing use of assisted living facilities necessitate a better understanding of risk factors for adverse outcomes. Fever as a long-term risk factor in elderly populations remains understudied. METHODS: We analyzed data from 16,523 veterans in assisted living facilities between 2012-2022, examining the relationship between fever (defined as temperature ≥100.4°F) and mortality at 90-, 365-, and 730-days post-admission. Subjects were categorized by fever timing (none, at intake, or after intake), temperature severity, and percentage of days febrile. RESULTS: Fever at intake and fever after admission were associated with significantly increased mortality compared to no fever (p < .001) at all time points. Higher fever temperatures (>105°F) and a greater percentage of days febrile (>5 %) correlated with worse mortality. Patients with fever at intake and a few percentage of days febrile (<5 %) had an OR of 1.24 (95 % CI 1.01-1.53) for mortality by 1 year compared to patients who did not have a fever. High (>105°F) early fever had an OR of 1.46 (95 % CI 1.20-1.78), and early fever with many days febrile (>5 %) had an OR of 1.53 (95 % CI 1.33-1.75) for mortality at 730 days compared to patients with no fever. CONCLUSIONS: Fever in assisted living residents increases mortality risk for up to two years, depending on temperature severity and duration. These findings suggest a "long fever" phenomenon, where acute febrile episodes may have lasting consequences. Incorporating fever status into risk stratification may help identify high-risk patients requiring enhanced monitoring and care.