Hypernatremia in Cardiogenic Shock: Effect on Kidney Outcomes, Mortality, and Critical Illness Myopathy in a Multicenter Cohort Study

Background: Hypernatremia in critically ill patients is associated with adverse outcomes, but its specific impact among patients with cardiogenic shock (CS) remains underexplored. We aimed to assess whether coexisting hypernatremia worsens renal, survival, and neuromuscular outcomes in CS patients. Methods: Using the TriNetX Global Collaborative Network (148 HCOs), we identified adult patients (≥18 years) hospitalized with CS (ICD-10: R57.0). Cohort A (n=36,443) included patients with coexisting hypernatremia (E87.0); Cohort B (n=217,142) had CS without hypernatremia. Outcomes assessed included mortality, acute kidney injury (AKI, N17), end-stage renal disease (ESRD, N18.6/Z99.2), critical illness myopathy (CIM, G72.81), ECMO and LVAD use. Kaplan-Meier survival and hazard ratios were used to compare time-to-event outcomes. No propensity matching was applied. Results: Compared to the normonatremic group, patients with CS and hypernatremia had significantly worse outcomes: Mortality: 52.4% vs. 41.6% (OR 1.54; 95% CI 1.51–1.58; p<0.001) AKI: 52.0% vs. 36.2% (OR 1.91; 95% CI 1.87–1.95; p<0.001) ESRD or dialysis dependence: 9.8% vs. 8.7% (OR 1.14; 95% CI 1.10–1.18; p<0.001) ECMO use: 1.1% vs. 0.5% (OR 2.28; p<0.001) LVAD placement: 1.9% vs. 1.5% (OR 1.28; p<0.001) Critical illness myopathy: 3.8% vs. 0.8% (OR 4.59; 95% CI 4.27–4.92; p<0.001) Patients with hypernatremia also had significantly shorter median survival (247 vs. 998 days) and higher hazard of death (HR 1.21; p<0.001). Conclusion: In this large real-world analysis, hypernatremia in patients with cardiogenic shock was independently associated with higher mortality, AKI, critical illness myopathy, and increased use of advanced mechanical support. These findings suggest hypernatremia may be a marker of illness severity and a potential therapeutic target in shock management