Fever in Acute Stroke Worsens Prognosis: A Prospective Study

Abstract

Background and Purpose No definitive data are yet available on the effects of body temperature on neurological damage after cerebral ischemia in humans. Experimental animal models have provided much evidence, but to our knowledge, only two studies on the relationship between fever and prognosis of stroke in humans have been published. The aim of our study was to investigate the prognostic role of fever in the first 7 days of hospitalization in a cohort of patients admitted to our hospital for acute stroke. Methods We analyzed the data of 183 patients included in a prospective observational prognostic study. Vital status at 30 days was considered the main outcome and was obtained for all patients. Age, level of consciousness, and glycemia at the time of hospitalization were considered covariates for an exact logistic regression analysis. The maximum temperature recorded during the first 7 days dichotomized as “no or low fever” versus “high fever” was added to the model. Death within 10 days, taken as a secondary outcome suggestive of death from neurological causes, was analyzed with exact permutation tests. Results Of the 183 patients analyzed in this study, 43% had fever during the first 7 days after hospitalization. The mean value of the maximum temperature recorded during the first 7 days in the 78 febrile patients was 38.3°C, and the median was 37.9°C. Onset of fever occurred in only 15% of febrile patients during the first day and in 49% on the second. The prognostic roles of age, level of consciousness, and glycemia were confirmed by exact logistic regression. Degree of consciousness impairment was the strongest prognostic variable, with an odds ratio (OR) of 11.4 (95% confidence interval [CI], 4.4 to 31.6). High fever (maximum temperature recorded during the first 7 days ≥37.9°C) was an independent factor for a worse prognosis, with an OR of 3.4 (95% CI, 1.2 to 9.5). The OR of dying within 10 days versus dying between 11 and 30 days was 4.9 (95% CI, 1.2 to 25.2) in patients with high fever with respect to all other patients. Conclusions Fever in the first 7 days was an independent predictor of poor outcome during the first month after a stroke. No data were available on the underlying causes of fever, but the higher risk of death in the first 10 days, most frequently attributed to neurological mechanisms, suggested that high temperature was an independent component of poor prognosis and not only an epiphenomenon of other complications in the course after a stroke. In agreement with animal studies, we found that patients with higher temperature had a worse stroke outcome.