ODP325 Inverse Relationship Between IL-6 and Sodium Levels in Patients With COVID-19 and Other Respiratory Tract Infections

Abstract

Abstract Background Hyponatremia is highly prevalent in patients with COVID-19. One of the most common causes of hyponatremia in these patients is the syndrome of inadequate antidiuresis (SIAD). Interleukin 6 (IL-6) is a key mediator of inflammation in COVID-19. We hypothesized that hyponatremia in COVID-19 is due to IL-6 mediated non-osmotic arginine vasopressin (AVP) secretion, and that the inverse association between IL-6 and plasma sodium concentration is stronger in COVID-19 compared to other respiratory infections. METHODS This is a secondary analysis of a prospective, observational, cohort study including patients with COVID-19 suspicion admitted to the Emergency Department, University Hospital of Basel, Switzerland, between March and July 2020. We included patients with PCR-confirmed COVID-19 and patients without COVID-19 but similar symptoms, further subclassified in bacterial and other viral respiratory infections. The primary objective was to investigate the association between plasma sodium levels and IL-6 levels. Results 500 patients were included, of whom 184 (37%) with COVID-19, 92 (18%) with bacterial respiratory infections, 224 (45%) with other viral respiratory infections. Hyponatremia prevalence was higher in patients with COVID-19 compared to patients with other viral respiratory infections (28% vs 12%, p<0. 01), and similar to patients with bacterial respiratory infections (28% vs 30%, p<0.41). In all three groups, median [IQR] IL-6 levels were significantly higher in hyponatremic compared to normonatremic patients (COVID-19: 43.4 [28.4, 59.8] vs 9.2 [2.8, 32.7] pg/ml, p<0. 0001; bacterial: 122.1 [63. 0, 282. 0] vs 67.1 [24.9, 252. 0] pg/ml, p<0. 05; viral: 14.1 [6.9, 84.7] vs 4.3 [2.1, 14.4] pg/ml, p<0. 05). IL-6 levels were negatively correlated with plasma sodium levels in COVID-19, whereas the correlation in bacterial and other viral infections was weaker (COVID-19: ρ = − 0.52, p < 0. 001; bacterial: ρ = − 0.24, p = 0. 056, viral: ρ = − 0.24, p < 0. 001). Conclusion IL-6 levels were inversely correlated with plasma sodium levels, with a stronger correlation in patients with COVID-19 compared to patients with bacterial and other viral infections. IL-6 might stimulate AVP secretion and lead to higher rates of hyponatremia due to the syndrome of inadequate antidiuresis in these patients. Presentation: No date and time listed