On the optimal sodium correction rate in hyponatraemia and clinical outcome: a meta-analysis

Background: Hyponatraemia is associated with greater mortality in emergency patients. Therefore, the correction of low serum sodium levels remains an important field in clinical practice. Methods: Eligible studies were searched through a literature query in PubMed and Web of Science in August 2024. Sodium correction rates and mortality data were extracted. The articles were grouped based on the threshold used to distinguish between slow and rapid correction. For each group, a random effects model was used for meta-analysis. The sodium correction rate thresholds were 8, 10 and 12 mmol/L/24 hours. Additionally, a random effects model was used to estimate the difference in osmotic demyelination syndrome (ODS) incidence. Results: 11 retrospective studies with a total of 27 672 cases were included in the meta-analysis, each scoring at least 8* on the Newcastle-Ottawa quality assessment score. Mortality was significantly lower in the rapid correction group compared with the slow correction group for the 8 mmol/L/day threshold (OR: 0.398, p<0.001), for 10 mmol/L/day (OR: 0.489, p<0.001) and for 12 mmol/L/day (OR: 0.57, p<0.001). Overall incidence of ODS was low (0.085%), but it was higher in the rapid correction group (OR: 3.959, p=0.002). Conclusion: Within all three thresholds of sodium correction, rapid correction was associated with improved survival. Although no causal relation can be concluded, a more liberal approach to sodium correction rate in hyponatraemia may be beneficial. However, osmotic demyelination remains a serious, although very rare, issue.