The association between the degree of fever as measured in the emergency department and clinical outcomes of hospitalized adult patients.

ABSTRACT

BACKGROUND: Fever is a physiologic response to a wide range of pathologies and one of the most common complaints and clinical signs in the emergency medicine department (ED). The association between fever magnitude and clinical outcomes has been evaluated in specific populations with inconsistent results. OBJECTIVES: In this study we aimed to investigate the association between the degree of fever in the ED and clinical outcomes of hospitalized febrile adult patients. METHODS: This was a retrospective single-center cohort study of all the patients with maximal body temperature (BT) ≥ 38.0 °C, as recorded during the ED evaluation, who were hospitalized between January 2015 and December 2020. Patients with heatstroke were excluded. The primary outcome was 30-day all-cause mortality and secondary outcomes were intensive care unit (ICU) admission and development of acute kidney injury (AKI). RESULTS: Fever was recorded among 8.1% of patients evaluated in the ED. Elevated BT was associated with increased risk of hospital admission (70.3% vs. 49.4%, p < 0.001), 30-day mortality (12.3% vs. 2.6%, p < 0.001), ICU admission (5.7% vs. 2.8%, p < 0.001), and AKI 11.7% vs. 3.8%, p < 0.001). After exclusion of nine patients with heatstroke, 21,252 hospitalized febrile patients were included in the final analysis. BT > 39.7 °C was progressively associated with increased mortality (OR 1.64-2.22, 95% CI 1.16-2.81, p < 0.005) as compared to BT 38.0-38.1 °C. More AKI events were observed in patients with BT > 39.5 °C (OR 1.48-2.91, 95% CI 1.11-3.66, p < 0.007). Temperature between 39.2 and 39.5 °C was associated with lower mortality (OR 0.62-0.71, 95% CI 0.51-0.87, p < 0.001). In a multiple logistic regression analysis BT > 39.9 °C was independently associated with increased mortality and AKI. BT > 39.7 °C was progressively associated with an increased risk of ICU admission. CONCLUSION: Among febrile patients admitted to the hospital, BT > 39.5 °C was associated with adverse clinical course, as compared to patients with lower-grade fever (38.0-38.1 °C). These patients should be flagged on arrival to the ED and likely warrant more aggressive evaluation and treatment.