title: Prognostic value of hyponatremia in heart failure patients: an analysis of the Clinical Characteristics and Outcomes in the Relation with Serum Sodium Level in Asian Patients Hospitalized for Heart Failure (COAST) study.
abstract: OBJECTIVE
  Hyponatremia is a well-known risk factor for poor outcomes in Western studies of heart failure (HF) patients. We evaluated the predictive value of hyponatremia in hospitalized Asian HF patients.
  
  
  METHODS
  The Clinical Characteristics and Outcomes in the Relation with Serum Sodium Level in Asian Patients Hospitalized for Heart Failure (the COAST) study enrolled hospitalized patients with systolic HF (ejection fraction < 45%) at eight centers in South Korea, Taiwan, and China. The relationship between admission sodium level and clinical outcomes was analyzed in 1,470 patients.
  
  
  RESULTS
  The mean admission sodium level was 138 ± 4.7 mmol/L, and 247 patients (16.8%) had hyponatremia defined as Na(+) < 135 mmol/L. The 12-month mortality was higher in hyponatremic patients (27.9% vs. 14.6%, p < 0.001), and hyponatremia was an independent predictor of 12-month mortality (hazard ratio, 1.72; 95% confidence interval, 1.12 to 2.65). During hospital admission, 57% of hyponatremic patients showed improvement without improvement in their clinical outcomes (p = 0.620). The proportion of patients with optimal medical treatment was only 26.5% and 44.2% at admission and discharge, respectively, defined as the combined use of angiotensin-converting-enzyme inhibitor/angiotensin receptor blocker and β-blocker. Underuse of optimal medical treatment was more pronounced in hyponatremic patients.
  
  
  CONCLUSIONS
  In hospitalized Asian HF patients, hyponatremia at admission is common and is an independent predictor of poor clinical outcome. Furthermore, hyponatremic patients receive less optimal medical treatment than their counterparts.
authors.affiliation: Department of Internal Medicine, Wonju Severance Christian Hospital, Yonsei University Wonju College of Medicine, Wonju, Korea.
authors.forename: Byung-Su
authors.initials: BS
authors.lastname: Yoo
authors.affiliation: Cardiovascular Center, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Jin Joo
authors.initials: JJ
authors.lastname: Park
authors.affiliation: Cardiovascular Center, Seoul National University Bundang Hospital, Seongnam, Korea.
authors.forename: Dong-Ju
authors.initials: DJ
authors.lastname: Choi
authors.affiliation: Department of Internal Medicine, Severance Hospital, Yonsei University Health System, Seoul, Korea.
authors.forename: Seok-Min
authors.initials: SM
authors.lastname: Kang
authors.affiliation: Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Juey-Jen
authors.initials: JJ
authors.lastname: Hwang
authors.affiliation: Department of Internal Medicine, Taipei Veterans General Hospital, Taipei, Taiwan.
authors.forename: Shing-Jong
authors.initials: SJ
authors.lastname: Lin
authors.affiliation: Department of Internal Medicine, Chang Gung Memorial Hospital, Linkou, Taiwan.
authors.forename: Ming-Shien
authors.initials: MS
authors.lastname: Wen
authors.affiliation: Department of Internal Medicine, Fuwai Hospital, Beijing, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Internal Medicine, Zhongshan Hospital, Shanghai, China.
authors.forename: Junbo
authors.initials: J
authors.lastname: Ge
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001208:Asia / Q000453:epidemiology; D044466:Asian People; D015415:Biomarkers / Q000097:blood; D002317:Cardiovascular Agents / Q000627:therapeutic use; D018572:Disease-Free Survival; D005260:Female; D019983:Guideline Adherence; D054625:Healthcare Disparities; D006333:Heart Failure / Q000175:diagnosis* / Q000188:drug therapy / Q000208:ethnology / Q000401:mortality / Q000503:physiopathology; D006760:Hospitalization; D006801:Humans; D007010:Hyponatremia / Q000097:blood / Q000175:diagnosis* / Q000188:drug therapy / Q000208:ethnology / Q000401:mortality; D008297:Male; D008875:Middle Aged; D017410:Practice Guidelines as Topic; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012307:Risk Factors; D012964:Sodium / Q000097:blood*; D013318:Stroke Volume; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; D002317:Cardiovascular Agents; D012964:Sodium
keywords: East Asians; Hospitalized heart failure; Hyponatremia; Predictor of clinical outcomes