Early peak temperature and mortality in critically ill patients with or without infection

To determine whether fever is associated with an increased or decreased risk of death in patients admitted to an intensive care unit (ICU) with infection. We evaluated the independent association between peak temperature in the first 24 h after ICU admission and in-hospital mortality according to whether there was an admission diagnosis of infection using a database of admissions to 129 ICUs in Australia and New Zealand (ANZ) (n = 269,078). Subsequently, we sought to confirm or refute the ANZ database findings using a validation cohort of admissions to 201 ICUs in the UK (n = 366,973). A total of 29,083/269,078 (10.8%) ANZ patients and 103,191/366,973 (28.1%) of UK patients were categorised as having an infection. In the ANZ cohort, adjusted in-hospital mortality risk progressively decreased with increasing peak temperature in patients with infection. Relative to the risk at 36.5-36.9A degrees C, the lowest risk was at 39-39.4A degrees C (adjusted OR 0.56; 95% CI 0.48-0.66). In patients without infection, the adjusted mortality risk progressively increased above 39.0A degrees C (adjusted OR 2.07 at 40.0A degrees C or above; 95% CI 1.68-2.55). In the UK cohort, findings were similar with adjusted odds ratios at corresponding temperatures of 0.77 (95% CI 0.71-0.85) and 1.94 (95% CI 1.60-2.34) for infection and non-infection groups, respectively. Elevated peak temperature in the first 24 h in ICU is associated with decreased in-hospital mortality in critically ill patients with an infection; randomised trials are needed to determine whether controlling fever increases mortality in such patients.