STOCKHOLM — Body temperature may be a cheap and easy way to gauge the prognosis of patients hospitalized for heart failure, according to a retrospective analysis of data from more than 300 patients.
Patients hospitalized for heart failure and who had hypothermia (a body temperature of 96.5° F) at the time of admission were nearly fourfold more likely to die during follow-up than were patients who were normothermic at admission, Mihai Gheorghiade, M.D., said at the annual congress of the European Society of Cardiology.
“This is the first report [of a hypothermia-prognosis link], so we need to be careful. It needs validation before making any conclusion that temperature is a prognostic factor,” said Dr. Gheorghiade, professor of medicine at Northwestern University, Chicago.
It is also unclear what physiologic process might link hypothermia with an increased risk of death among heart failure patients. Some possible explanations are that hypothermia reflects reduced cardiac output, neurohormonal activation, or an inflammatory response, or hypothermia may result from socioeconomic factors that also may exacerbate heart failure, said Dr. Gheorghiade, who is also with Northwestern's division of cardiology.
The correlation was made by reviewing data collected in a study designed to test the safety and efficacy of tolvaptan, an oral vasopressin receptor antagonist, in patients with systolic dysfunction who were hospitalized for worsening heart failure.
Of the 319 patients enrolled in the study, body temperature readings on admission were available for 315. Of those patients, 32 had hypothermia, with an average body temperature of 95.9° F. The other 283 patients had an average temperature of 97.7° F.
During the 60 days following hospital admission, mortality was 9.4% in the patients with hypothermia and 5.9% in those who were normothermic at admission. When investigators adjusted for baseline differences in blood urea nitrogen, age, and tolvaptan treatment, the patients with hypothermia were 3.9 times more likely to die than were patients with no hypothermia.
“I think that from now on, in clinical trials of heart failure, we should carefully measure body temperature at admission and also day after day to correlate temperature with worsening heart failure,” Dr. Gheorghiade said.