Early serum sodium variability and mortality in critically ill patients with cerebral infarction: a retrospective...

Dysnatremia is common in cerebral infarction and associated with poor outcomes. However, the prognostic significance of early dynamic changes in serum sodium, as opposed to static admission values, remains poorly understood.

This retrospective cohort study utilized data from the Medical Information Mart for Intensive Care IV (MIMIC-IV) database. Adult ICU patients with cerebral infarction were included. Sodium variability was quantified using the coefficient of variation (CV) of all measurements within the first 72 h. The primary outcome was 30-day all-cause mortality. Secondary outcomes included in-hospital mortality and ICU mortality. Multivariable Cox regression and restricted cubic spline analyses were employed to assess the independent and nonlinear associations.

Among 3764 patients, increased sodium variability demonstrated a strong, dose-response relationship with higher mortality. After full adjustment for confounders, each unit increase in CV was associated with a 22% increased risk of 30-day mortality (HR 1.22, 95% CI 1.16-1.28). Patients in the highest variability quartile (Q4) had over a twofold risk of mortality (HR 2.02, 95% CI 1.62-2.50) compared to the lowest (Q1). A nonlinear relationship was identified, with steeper risk increases at lower CV values.

Early serum sodium variability is an independent predictor of short-term mortality in critically ill patients with cerebral infarction, highlighting the importance of dynamic sodium monitoring and stability as a potential target for therapeutic intervention.