title: Prevalence and Prognostic Significance of Hyponatremia in Patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease: Data from the Akershus Cardiac Examination (ACE) 2 Study.
abstract: BACKGROUND
  Hyponatremia is prevalent and associated with mortality in patients with heart failure (HF). The prevalence and prognostic implications of hyponatremia in acute exacerbation of chronic obstructive pulmonary (AECOPD) have not been established.
  
  
  METHODS
  We included 313 unselected patients with acute dyspnea who were categorized by etiology of dyspnea according to established guidelines (derivation cohort). Serum Na+ was determined on hospital admission and corrected for hyperglycemia, and hyponatremia was defined as [Na+]<137 mmol/L. Survival was ascertained after a median follow-up of 816 days and outcome was analyzed in acute HF (n = 143) and AECOPD (n = 83) separately. Results were confirmed in an independent AECOPD validation cohort (n = 99).
  
  
  RESULTS
  In the derivation cohort, median serum Na+ was lower in AECOPD vs. acute HF (138.5 [135.9-140.5] vs. 139.2 [136.7-141.3] mmol/L, p = 0.02), while prevalence of hyponatremia (27% [22/83] vs. 20% [29/143], p = 0.28) and mortality rate (42% [35/83] vs. 46% [66/143], p = 0.56) were similar. By univariate Cox regression analysis, hyponatremia was associated with increased mortality in acute HF (HR 1.85 [95% CI 1.08, 3.16], p = 0.02), but not in AECOPD (HR 1.00 [0.47, 2.15], p = 1.00). Analogous to the results of the derivation cohort, hyponatremia was prevalent also in the AECOPD validation cohort (25% [25/99]), but not associated with mortality. The diverging effect of hyponatremia on outcome between AECOPD and acute HF was statistically significant (p = 0.04).
  
  
  CONCLUSIONS
  Hyponatremia is prevalent in patients with acute HF and AECOPD, but is associated with mortality in patients with acute HF only.
authors.affiliation: Division of Medicine, Akershus University Hospital, Lørenskog, Norway.|Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors.forename: Jacob A
authors.identifier: http://orcid.org/0000-0003-2158-786X
authors.initials: JA
authors.lastname: Winther
authors.affiliation: Division of Medicine, Akershus University Hospital, Lørenskog, Norway.|Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors.forename: Jon
authors.initials: J
authors.lastname: Brynildsen
authors.affiliation: Division of Medicine, Akershus University Hospital, Lørenskog, Norway.|Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors.forename: Arne Didrik
authors.initials: AD
authors.lastname: Høiseth
authors.affiliation: Division of Medicine, Akershus University Hospital, Lørenskog, Norway.|Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors.forename: Ivar
authors.initials: I
authors.lastname: Følling
authors.affiliation: Division of Medicine, Akershus University Hospital, Lørenskog, Norway.|Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors.forename: Pål H
authors.initials: PH
authors.lastname: Brekke
authors.affiliation: Institute of Clinical Medicine, University of Oslo, Oslo, Norway.|Institute for Experimental Medical Research, Oslo University Hospital, Ullevål, Oslo, Norway.
authors.forename: Geir
authors.initials: G
authors.lastname: Christensen
authors.affiliation: Institute of Clinical Medicine, University of Oslo, Oslo, Norway.|Division of Diagnostics and Technology, Akershus University Hospital, Lørenskog, Norway.
authors.forename: Tor-Arne
authors.initials: TA
authors.lastname: Hagve
authors.affiliation: Division of Endocrinology and Metabolism, Georgetown University Medical Center, Washington, DC, United States of America.
authors.forename: Joseph G
authors.initials: JG
authors.lastname: Verbalis
authors.affiliation: Division of Medicine, Akershus University Hospital, Lørenskog, Norway.|Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors.forename: Torbjørn
authors.initials: T
authors.lastname: Omland
authors.affiliation: Division of Medicine, Akershus University Hospital, Lørenskog, Norway.|Institute of Clinical Medicine, University of Oslo, Oslo, Norway.
authors.forename: Helge
authors.initials: H
authors.lastname: Røsjø
mesh_terms: D000208:Acute Disease; D000368:Aged; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007010:Hyponatremia / Q000150:complications* / Q000175:diagnosis*; D008297:Male; D015995:Prevalence; D011379:Prognosis; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications*