Reversal of neutrophil-to-lymphocyte count ratio in early versus late death from septic shock

Abstract

Introduction: Septic shock is one of the most frequent causes of admission to the intensive care unit (ICU) and is associated with a poor prognosis. Early and late death in septic shock should be distinguished because they may involve different underlying mechanisms. In various conditions, the neutrophil-to-lymphocyte count ratio (NLCR) has been described as an easily measurable parameter to express injury severity. In the present study, we investigated whether the timing of death was related to a particular NLCR. Methods: We conducted a prospective, single-center, observational study that included consecutive septic shock patients. Severity scores, early (before day 5) or late (on or after day 5 of septic shock onset) ICU mortality, and daily leukocyte counts were collected during the ICU stay. We assessed the association between leukocyte counts at admission and their evolution during the first 5 days with early or late death. The association between patient characteristics (including cell counts) and prognosis was estimated using Cox proportional cause-specific hazards models. Results: The study included 130 patients who were diagnosed with abdominal (n = 99) or extra-abdominal (n = 31) septic shock. The median (interquartile range) NLCR was 12.5 (6.5-21.2) in survivors and 6.2 (3.7-12.6) in nonsurvivors (p = 0.001). The NLCR at admission was significantly lower in patients who died before day 5 than in survivors (5 [3.5-11.6] versus 12.5 [6.5-21.2], respectively; p = 0.01). From day 1 to day 5, an increased NLCR related to an increase in neutrophil count and a decrease in lymphocyte count was associated with late death (+34.8 % [-8.2 to 305.4] versus -20 % [-57.4 to 45.9]; p = 0.003). Those results were present in patients with abdominal origin sepsis as well as in those with extra-abdominal sepsis, who were analyzed separately. Conclusions: In the present study, a reversed NLCR evolution was observed according to the timing of death. Septic shock patients at risk of early death had a low NLCR at admission, although late death was associated with an increased NLCR during the first 5 days.