The impact of serum sodium variability on surgical patients with aneurysmal subarachnoid hemorrhage

Currently, limited evidence exists on the impact of serum sodium variability in patients with aneurysmal subarachnoid hemorrhage (SAH) who underwent surgical clipping. We aimed to perform a detailed examination of the relationship between sodium variability and mortality in these patients. We conducted a cohort study including adult patients with aneurysmal SAH who underwent surgical clipping at a university hospital. Propensity score matching (PSM) was used to match patients’ baseline characteristics. We evaluated the association between serum sodium standard deviation and mortality. Net reclassification improvement was calculated to assess and compare the reclassification capacity of different models. Trends in serum sodium over time were detected using linear mixed-effects models. Of 563 aneurysmal SAH patients who underwent surgical clipping during the study period, the average age was 56.87 ± 10.81 years. The serum sodium standard deviation was 4.24 [2.65–5.82] mmol/L. Patients with high sodium variability had significantly higher odds of mortality (adjusted odds ratio [aOR]: 1.93, 95% confidence interval [CI]: 1.01 to 3.68; P = 0.045). PSM analysis showed similar results (aOR: 2.23, 95% CI: 1.10 to 4.99; P = 0.045). Additionally, an increase in serum sodium of more than 5 mmol/L was significantly associated with mortality (aOR: 3.46, 95% CI: 1.26 to 9.20; P = 0.016) in a linear dose-response pattern. High serum sodium variability and an increase in serum sodium of more than 5 mmol/L were independent predictive factors of mortality in aneurysmal SAH patients who underwent surgical clipping. Thus, even mild changes in sodium levels warrant close attention.