Epidemiology and outcomes of fever burden among patients with acute ischemic stroke

Abstract

Background and purpose: Although fever following ischemic stroke is common and has been associated with poor patient outcomes, little is known about which aspects of fever (eg, frequency, severity, or duration) are most associated with outcomes.

Methods: We used data from a retrospective cohort of acute ischemic stroke patients who were admitted to 1 of 5 hospitals (1998-2003). A fever event was defined as a period with a temperature≥100.0 °F (37.8 °C). Fever burden was defined as the maximum temperature (Tmax) minus 100.0 °F, multiplied by the number of days with a fever. Fever burden (in degree-days) was categorized as low (0.1-2.0), medium (2.1-4.0), or high (≥4.0). Logistic regression was used to evaluate the adjusted association of any fever episode and fever burden with the combined outcome of in-hospital mortality or discharge to hospice.

Results: Among 1361 stroke patients, 483 patients (35.5%) had ≥1 fever event. Among febrile patients, the median Tmax was 100.9 °F (range, 100.0-106.6 °F), 87% had ≤2 events and median total fever days was 2. Patients with any fever event had higher combined outcome rates after adjusting for demographics, stroke severity, and clinical characteristics: adjusted odds ratio (aOR), 2.7 (95% CI, 1.6-4.4). Higher fever burden was also associated with the combined outcome: high burden aOR, 6.7 (95% CI, 3.6-12.7); medium burden aOR, 3.9 (95% CI, 1.9-8.2); and low burden aOR, 1.2 (95%CI, 0.6-2.3) versus no fever.

Conclusions: This study confirms that poststroke fever occurs commonly and demonstrates that patients with high fever burden have a 6-fold increased odds of death or discharge to hospice.