Effects of Poststroke Pyrexia on Stroke Outcome

Abstract

Background and Purpose-The effect of pyrexia on cerebral ischemia has been extensively studied in animals. In humans, however, such studies are small and the results conflicting. We undertook a meta-analysis using all such published studies on the effect of hyperthermia on stroke outcome. Methods-Three databases were searched for all published studies that examined the relationship of raised temperature after stroke onset and eventual outcome. Combined probability values and odds ratios were obtained. A heterogeneity test was performed to ensure that the data were suitable for such an analysis. Morbidity and mortality were used as outcome measures. Results-Nine studies were identified totaling 3790 patients, providing our study with 99% power to detect a 9% increase in morbidity and 84% power to detect a 1% increase in mortality for the pyrexial group. The combined odds ratio for mortality was 1.19 (95% CI, 0.99 to 1.43). A heterogeneity test was highly nonsignificant (PϾ0.05) for mortality, suggesting that the data were sufficiently similar to be meta-analyzed. Combined probability values were highly significant for both morbidity (PϽ0.0001) and mortality (PϽ0.00000001). Conclusions-The results from this meta-analysis suggest that pyrexia after stroke onset is associated with a marked increase in morbidity and mortality. Measures should be taken to combat fever in the clinical setting to prevent stroke progression. The possible benefit of therapeutic hypothermia in the management of acute stroke should be further investigated. Key Words: fever Ⅲ meta-analysis Ⅲ outcome Ⅲ stroke S troke remains one of the leading causes of morbidity and mortality in the western world. Several factors have been implicated in influencing the extent of cerebral damage in acute stroke, such as high or low systolic blood pressure, 1 elevated blood glucose, and a high temperature. 2 Rodent models have consistently shown hyperthermia to be a reliable predictor of stroke outcome. One study found that elevation of rat body temperature to 40°C 24 hours after induced cerebral infarction resulted in a 3-fold increase in cerebral infarct volume. 3 Significant results were also obtained after experimental traumatic injury, with a 2.6-fold increase in rat mortality and a 13-fold increase of cerebral contusion volume. 3 Other studies have found significant effects on stroke outcome in rats with lesser degrees of hyperthermia. 2,4,5 Furthermore, it has been shown that induced hypothermia has a protective effect up to 1 hour after focal permanent ischemia. 6 In humans, however, the relationship between fever and stroke outcome has been far less extensively investigated, with studies incorporating small numbers of patients and, as recently emphasized, 7 providing conflicting results. There are no large-scale prospective studies assessing outcome between normothermic and hyperthermic patients.We sought to undertake a meta-analysis on all published studies to investigate the effect of body temperature on stroke outcome in humans. Combining the resul...

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