The Presence of Hypothermia Within 24 Hours of Sepsis Diagnosis Predicts Persistent Lymphopenia

Objective: To determine whether hypothermia within 24 hours of sepsis diagnosis is associated with development of persistent lymphopenia, a feature of sepsis-induced immunosuppression. Design: Retrospective cohort study. Setting: A 1,200-bed university-affiliated tertiary care hospital. Patients: Adult patients diagnosed with bacteremia and sepsis within 5 days of hospital admission between January 1, 2010, and July 31, 2012. Interventions: None. Measurements and Main Results: Leukocyte counts were recorded during the first 4 days following sepsis diagnosis. Persistent lymphopenia was defined as an absolute lymphocyte count less than 1.2 cells/μL × 10 3 present on the fourth day after diagnosis. Of the 445 patients with sepsis included, hypothermia developed in 64 patients (14.4%) (defined as a body temperature < 36.0°C) within 24 hours of sepsis diagnosis. Hypothermia was a significant independent predictor of persistent lymphopenia (adjusted odds ratio, 2.70 [95% CI, 1.10, 6.60]; p = 0.03) after accounting for age, disease severity, comorbidities, source of bacteremia, and type of organism. Compared with the nonhypothermic patients, hypothermic patients had higher 28-day (50.0% vs 24.9%, p < 0.001) and 1-year mortality (60.9% vs 47.0%, p = 0.001). Conclusions: Hypothermia is associated with higher mortality and an increased risk of persistent lymphopenia in patients with sepsis, and it may be an early clinical predictor of sepsis-induced immunosuppression.