Association of Hyponatremia and Risk of Short- and Long-Term Mortality in Patients with Stroke: A Systematic Review and Meta-Analysis

BackgroundHyponatremia is the most common electrolyte disorder in the clinic practice and it is closely related to the prognosis of various diseases. Studies reported that hyponatremia increased the risk of stroke mortality while yielded inconsistent findings during the follow-up period. Thus, a systematic review and meta-analysis to assess the relationship between hyponatremia and the short-term (within 90 days) and long-term (more than 1 year) prognosis of stroke patients was conducted.MethodsA computerized systematic literature search was performed before November of 2018 for relevant articles evaluating the relationship between hyponatremia and all-cause mortality risk in stroke patients. Pooled relative risk (RR) and hazard risk (HR) with 95% confidence interval (CI) were calculated using DerSimonian-Laird random-effects model. Subgroup analyses were performed according to the follow-up period, types of stroke, different controls, sample size, and sampling time.ResultsA total of 12 studies with 21,973 patients were identified. Compared to the nonhyponatremia patients, hyponatremia was associated with a higher risk of all-cause mortality in short-term (RR 1.61, 95% CI 1.33-1.96; HR 1.78 95% CI 1.19-2.75) and long-term follow-up (RR 1.77, 95% CI 1.27-2.47; HR 2.23,95% CI 1.30-3.82). Subgroups analysis showed the similar results in most subgroups.ConclusionsThis meta-analysis concludes that hyponatremia has a significant prognostic value for short- and long-term prognosis to stroke patients.