title: Hyponatremia improvement is associated with a reduced risk of mortality: evidence from a meta-analysis.
abstract: BACKGROUND
  Hyponatremia is the most common electrolyte disorder and it is associated with increased morbidity and mortality. However, there is no clear demonstration that the improvement of serum sodium concentration ([Na(+)]) counteracts the increased risk of mortality associated with hyponatremia. Thus, we performed a meta-analysis that included the published studies that addressed the effect of hyponatremia improvement on mortality.
  
  
  RESULTS
  A Medline, Embase and Cochrane search was performed to retrieve all English-language studies of human subjects published up to June 30th 2014, using the following words: "hyponatremia", "hyponatraemia", "mortality", "morbidity" and "sodium". Fifteen studies satisfied inclusion criteria encompassing a total of 13,816 patients. The identification of relevant abstracts, the selection of studies and the subsequent data extraction were performed independently by two of the authors, and conflicts resolved by a third investigator. Across all fifteen studies, any improvement of hyponatremia was associated with a reduced risk of overall mortality (OR=0.57[0.40-0.81]). The association was even stronger when only those studies (n=8) reporting a threshold for serum [Na(+)] improvement to >130 mmol/L were considered (OR=0.51[0.31-0.86]). The reduced mortality rate persisted at follow-up (OR=0.55[0.36-0.84] at 12 months). Meta-regression analyses showed that the reduced mortality associated with hyponatremia improvement was more evident in older subjects and in those with lower serum [Na(+)] at enrollment.
  
  
  CONCLUSIONS
  This meta-analysis documents for the first time that improvement in serum [Na(+)] in hyponatremic patients is associated with a reduction of overall mortality.
authors.affiliation: Endocrinology Unit, Maggiore-Bellaria Hospital, Bologna, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Corona
authors.affiliation: Endocrine Unit, "Center for Research, Transfer and High Education on Chronic, Inflammatory, Degenerative and Neoplastic Disorders for the Development of Novel Therapies" (DENOThe), Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Careggi Hospital, 50139, Florence, Italy.
authors.forename: Corinna
authors.initials: C
authors.lastname: Giuliani
authors.affiliation: Division of Endocrinology and Metabolism, Georgetown University, Washington, DC, 20007, United States of America.
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Verbalis
authors.affiliation: Endocrine Unit, "Center for Research, Transfer and High Education on Chronic, Inflammatory, Degenerative and Neoplastic Disorders for the Development of Novel Therapies" (DENOThe), Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Careggi Hospital, 50139, Florence, Italy.
authors.forename: Gianni
authors.initials: G
authors.lastname: Forti
authors.affiliation: Andrology Unit, "Center for Research, Transfer and High Education on Chronic, Inflammatory, Degenerative and Neoplastic Disorders for the Development of Novel Therapies" (DENOThe), Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Careggi Hospital, 50139, Florence, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Maggi
authors.affiliation: Endocrine Unit, "Center for Research, Transfer and High Education on Chronic, Inflammatory, Degenerative and Neoplastic Disorders for the Development of Novel Therapies" (DENOThe), Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, Careggi Hospital, 50139, Florence, Italy.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Peri
mesh_terms: D006801:Humans; D007010:Hyponatremia / Q000401:mortality / Q000503:physiopathology / Q000628:therapy*; D012307:Risk Factors