Does Immune Status Impact the Utility of SOFA Score in Predicting Outcomes in Necrotizing Soft Tissue Infections?

Author(s):
Manuel Castillo-Angeles ; Ramsis Ramsis; Elizabeth Bryant; Jeffrey Skubic; Matthew Giangola; Deepika Nehra; Stephanie Nitzschke; Ali Salim; Reza Askari

Background:

Sequential assessment of SOFA score is a good indicator of prognosis in NSTI patients. However, the prognostic value of the SOFA score in immunocompromised patients with NSTI has not been described. Our aim was to determine the impact of immune status in the utility of the SOFA score and its change over time for predicting mortality in patients with NSTI.

Hypothesis:

We hypothesize that immune status decreases the utility of the SOFA score in predicting mortality in patients with NSTI.

Methods:

This is a retrospective cohort study of NSTI patients admitted from 1995 to 2014. SOFA scores were calculated at baseline (T0), 24 (T1), 48 (T2) and 72 (T3) hours after admission. ΔSOFA was also calculated (change in SOFA from T0 to T1, T2 and T3). Multivariate logistic regression was performed to assess the association between SOFA score and in-hospital mortality. Subgroup analysis was performed based on immune status.

Results:

There were 509 total patients, 57% males and a median age of 57 years (IQR 46–67). 132 (26%) were immunocompromised. Overall in-hospital mortality was 15% and 23% in immunocompromised patients. Sofa scores at T0, T1, T2 and T3 were significantly different between survivors and non-survivors (Table 1). However, when compared by immune status, only Sofa score at T1 was significantly different between immunocompetent and immunocompromised patients (Table 2). On multivariate analysis, SOFA score and change in the score over time were predictive of mortality in immunocompetent patients. However, SOFA score and change over time were not predictive of mortality for immunocompromised patients.

Conclusions:

While in immunocompetent NSTI patients, sequential assessment of SOFA score correlated with mortality, that was not true in immunocompromised patients.