title: Recovery from hyponatremia in acute phase is associated with better in-hospital mortality rate in acute heart failure syndrome.
abstract: BACKGROUND
  Although hyponatremia on admission is a predictor of poor prognosis in acute heart failure (AHF) patients, little is known about the association between changes in sodium level in acute phase and in-hospital mortality. This study was performed to clarify the impact of sodium level improvement in the early phase on prognosis in AHF patients.
  
  
  METHODS
  A total of 882 consecutive hospitalized AHF patients were retrospectively enrolled in this study. Sodium levels were evaluated on days 1 and 3 of admission, and patients were classified into three groups: patients with hyponatremia on admission and day 3 (hypo-hypo group); patients with hyponatremia on admission and normonatremia on day 3 (hypo-normo group); and patients with normonatremia on admission (normo group).
  
  
  RESULTS
  Hyponatremia (sodium ≤135 mEq/L) was observed in 14.3% of cases. In multivariate linear regression analysis, age (standardized beta=0.084), male gender (standardized beta=-0.072), history of ischemic heart disease (standardized beta=-0.069), baseline sodium level (standardized beta=-0.435), and tolvaptan use (standardized beta=0.093) were independent determinants of changes in sodium level from day 1 to day 3. In-hospital mortality rates were significantly higher in the hypo-hypo group (23.7%) and hypo-normo group (9.7%) than the normo group (6.9%) (p<0.001). After adjustment for covariates, both hypo-normo (OR: 0.28, 95% CI: 0.08-0.93, p=0.038) and normo (OR: 0.42, 95% CI: 0.20-0.88, p=0.022) groups showed significantly lower in-hospital mortality rates than the hypo-hypo group.
  
  
  CONCLUSIONS
  Early recovery from hyponatremia in AHF patients is associated with lower in-hospital mortality rate.
authors.affiliation: Department of Cardiology, Kameda Medical Center, Chiba, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Yoshioka
authors.affiliation: Department of Cardiology, Kameda Medical Center, Chiba, Japan. Electronic address: yuya8950@gmail.com.
authors.forename: Yuya
authors.initials: Y
authors.lastname: Matsue
authors.affiliation: Department of Cardiology, The Sakakibara Heart Institute of Okayama, Okayama, Japan.
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Kagiyama
authors.affiliation: Department of Epidemiology, Harvard T. H. Chan School of Public Health, Boston, MA, USA.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Yoshida
authors.affiliation: Division of Cardiology, Kawasaki Medical School, Kurashiki, Japan.
authors.forename: Teruyoshi
authors.initials: T
authors.lastname: Kume
authors.affiliation: First Department of Internal Medicine, Nara Medical Universtiy, Kashihara, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Okura
authors.affiliation: Department of Cardiology, Kameda Medical Center, Chiba, Japan.
authors.forename: Makoto
authors.initials: M
authors.lastname: Suzuki
authors.affiliation: Department of Cardiology, Kameda Medical Center, Chiba, Japan.
authors.forename: Akihiko
authors.initials: A
authors.lastname: Matsumura
authors.affiliation: Department of Cardiology, The Sakakibara Heart Institute of Okayama, Okayama, Japan.
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Yoshida
authors.affiliation: Department of Cardiology, Kameda Medical Center, Chiba, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Hashimoto
mesh_terms: D000208:Acute Disease; D000367:Age Factors; D000368:Aged; D065092:Antidiuretic Hormone Receptor Antagonists / Q000627:therapeutic use; D001552:Benzazepines / Q000627:therapeutic use; D005260:Female; D006333:Heart Failure / Q000401:mortality* / Q000628:therapy; D017052:Hospital Mortality; D006801:Humans; D007010:Hyponatremia / Q000401:mortality* / Q000628:therapy*; D008297:Male; D017202:Myocardial Ischemia / Q000453:epidemiology; D011379:Prognosis; D012189:Retrospective Studies; D012737:Sex Factors; D000077602:Tolvaptan
chemical_list: D065092:Antidiuretic Hormone Receptor Antagonists; D001552:Benzazepines; D000077602:Tolvaptan
keywords: Acute heart failure; Hyponatremia; Prognosis