The continuing question of how fever duration is associated with patient outcome.

Although fever magnitude and etiology have been associated with outcomes of critically ill patients, possible associations between fever duration and mortality remain inconclusive. Since long-lasting fever is generally attributed to severe pathologic conditions, it is expected to be an indicator of adverse outcome. It also seems plausible that persistent fever in specific patient groups, mainly those with cerebral damage or limited cardiorespiratory reserve, could lead to worsened outcomes. Existing studies on these associations have been considerably limited because of methodological flaws, which may account for controversial findings that have been reported. Well-designed, large-sample studies using diverse measures of fever duration need to be conducted.