Factors associated with hyponatremia in patients with acute spinal cord injury: a systematic review and meta-analysis

BackgroundHyponatremia is a prevalent electrolyte disorder in patients with acute spinal cord injury (SCI), which can significantly increase the risk of adverse complications and impair long-term prognosis. Despite its clinical significance, the existing evidence on the factors associated with hyponatremia in this patient population remains fragmented and inconsistent, leading to uncertainties in clinical prevention and management.MethodsSystematic searches were conducted in PubMed, Embase, Web of Science, Cochrane Library, and Chinese databases including CNKI, Wan fang, and VIP, retrieving relevant studies from the inception of each database up to December 20, 2025. Included observational studies reporting factors associated with hyponatremia in patients with acute spinal cord injury. Two researchers independently performed literature screening, data extraction, and quality assessment. Results were synthesized using a random-effects model to calculate odds ratios (OR) with 95% confidence intervals (CI), with assessments of heterogeneity, publication bias, and sensitivity analyses.ResultsTwelve eligible studies involving 2,355 patients were included in the meta-analysis. The results indicate an association between upper cervical spine injury [OR = 6.05, 95%CI (2.79, 13.10)], complete SCI [OR = 5.35, 95%CI (3.15, 9.07)], hypoproteinemia [OR = 2.96, 95%CI (1.10, 7.92)], infection [OR = 2.20, 95%CI (1.67, 2.90)], and hyponatremia in patients with SCI.ConclusionThis meta-analysis demonstrates that hyponatremia in patients with acute SCI is closely related to the level and severity of spinal cord injury, with upper cervical spine injury and complete SCI being potential major risk indicators. Additionally, hypoproteinemia and infection are important associated factors. These findings highlight the need for targeted monitoring and intervention of high-risk patients to reduce the incidence of hyponatremia and improve clinical outcomes.