ICU Mortality is Increased in Septic Shock Patients Accompanied with Hypo- or Hyper- Serum Osmolarity: A Retrospective Study

Purpose: While many factors that are associated with increased mortality in septic shock patients have been identified, the effect of serum osmolarity to altering patient outcomes among ICU patients with septic shock has not been studied. This study was designed to examine the association of serum osmolarity with ICU 28-day mortality in that population. Methods: The MIMIC-IV database was employed to identify patients diagnosed with septic shock. The serum osmolarity was calculated according to the serum concentration of Na + , K + , glucose and urea nitrogen synchronously. The statistical approaches used included multivariate logistic regression, propensity score analysis, inverse probability-weighting and causal mediation analysis. Results: In this study, significant difference of 28-day mortality was observed in septic shock patients accompanied with hypo-osmolarity, hyper-osmolarity and normal osmolarity (30.8%, 35.0% and 23.0%, P<0.001) which was detected at ICU admission. We also found that transforming the hyper-osmolarity into normal osmolarity by fluid therapy in day 2 and day 3 would decrease this mortality. Conclusion: Serum abnormality is significantly associated with increased 28-day mortality in septic shock patients.