Prognostic Significance of Hyponatremia in Acute Stroke: A Systematic Review and Meta-Analysis

Abstract

<b><i>Objective:</i></b> Hyponatremia is a common electrolyte disorder in patients with stroke, which leads to various fatal complications. We performed a systematic review and meta-analysis to investigate the outcomes of acute stroke patients with hyponatremia. <b><i>Methods:</i></b> We searched MEDLINE, EMBASE, and the Cochrane Library databases for relevant literature in English published up to March 2020. Two review authors independently screened and selected the studies by assessing the eligibility and validity based on the inclusion criteria. Mortality at 90 days was set as the primary end point, and in-hospital mortality and length of hospital stay were set as the secondary end points. We conducted the data synthesis and analyzed the outcomes by calculating the odds ratio (OR) and mean difference. <b><i>Results:</i></b> Of 835 studies, 15 studies met the inclusion criteria (<i>n</i> = 10,745). The prevalence rate of stroke patients with hyponatremia was 7.0–59.2%. They had significantly higher 90-day mortality (OR, 1.73; 95% confidence interval (CI), 1.24–2.42) and longer length of hospital stay (mean difference, 10.68 days; 95% CI, 7.14–14.22) than patients without hyponatremia. Patients with hyponatremia had a higher tendency of in-hospital mortality than those without hyponatremia (OR, 1.61; 95% CI, 0.97–2.69). <b><i>Conclusions:</i></b> The development of hyponatremia in the clinical course of stroke is associated with higher short-term mortality and a longer hospital stay. Although the causal relationship is unclear, hyponatremia could be a significant predictor of poor outcomes after stroke.