title: The occurrence of hyponatremia and its importance as a prognostic factor in a cross-section of cancer patients.
abstract: Hyponatremia is prognostic of higher mortality in some cancers but has not been well studied in others. We used a longitudinal design to determine the incidence and prognostic importance of euvolemic and hypervolemic hyponatremia in patients following diagnosis with lymphoma, breast (BC), colorectal (CRC), small cell lung (SCLC), or non-small cell lung cancer (NSCLC).
  
  
  
  Medical record and tumor registry data from two large integrated delivery networks were combined for patients diagnosed with lymphoma, BC, CRC, or lung cancers (2002-2010) who had ≥1 administration of radiation/chemotherapy within 6 months of diagnosis and no evidence of hypovolemic hyponatremia. Hyponatremia incidence was measured per 1000 person-years (PY). Cox proportional hazard models assessed the prognostic value of hyponatremia as a time-varying covariate on overall survival (OS) and progression-free survival (PFS).
  
  
  
  Hyponatremia incidence (%, rate) was 76 % each, 1193 and 2311 per 1000 PY, among NSCLC and SCLC patients, respectively; 37 %, 169 in BC; 64 %, 637 in CRC, and 60 %, 395 in lymphoma. Hyponatremia was negatively associated with OS in BC (HR 3.7; P = <.01), CRC (HR 2.4; P < .01), lung cancer (HR 2.4; P < .01), and lymphoma (HR 4.5; P < .01). Hyponatremia was marginally associated with shorter PFS (HR 1.3, P = .07) across cancer types.
  
  
  
  The incidence of hyponatremia is higher than previously reported in lung cancer, is high in lymphoma, BC, and CRC and is a negative prognostic indicator for survival. Hyponatremia incidence in malignancy may be underestimated. The effects of hyponatremia correction on survival in cancer patients require further study.
authors.affiliation: Dana-Farber Cancer Institute, 450 Brookline Ave, M221, Boston, MA, 02215, USA. jorgej_castillo@dfci.harvard.edu.
authors.forename: Jorge J
authors.initials: JJ
authors.lastname: Castillo
authors.affiliation: Memorial Sloan-Kettering Cancer Center, New York, NY, USA.
authors.forename: Ilya G
authors.initials: IG
authors.lastname: Glezerman
authors.affiliation: Otsuka America Pharmaceutical, Inc, Princeton, NJ, USA.
authors.forename: Susan H
authors.initials: SH
authors.lastname: Boklage
authors.affiliation: Otsuka America Pharmaceutical, Inc, Princeton, NJ, USA.
authors.forename: Joseph
authors.initials: J
authors.lastname: Chiodo
authors.affiliation: Outcomes Research Solutions, Inc, Waltham, MA, USA.
authors.forename: Beni A
authors.initials: BA
authors.lastname: Tidwell
authors.affiliation: Henry Ford Health System, Detroit, USA.
authors.forename: Lois E
authors.initials: LE
authors.lastname: Lamerato
authors.affiliation: Outcomes Research Solutions, Inc, Waltham, MA, USA.
authors.forename: Kathy L
authors.initials: KL
authors.lastname: Schulman
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000150:complications / Q000628:therapy; D002289:Carcinoma, Non-Small-Cell Lung / Q000150:complications / Q000628:therapy; D059248:Chemoradiotherapy / Q000379:methods / Q000706:statistics & numerical data; D015179:Colorectal Neoplasms / Q000150:complications / Q000628:therapy; D005260:Female; D006801:Humans; D007010:Hyponatremia / Q000150:complications / Q000453:epidemiology*; D015994:Incidence; D008137:Longitudinal Studies; D008175:Lung Neoplasms / Q000150:complications / Q000628:therapy; D008223:Lymphoma / Q000150:complications / Q000628:therapy; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000150:complications / Q000628:therapy*; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D055752:Small Cell Lung Carcinoma / Q000150:complications / Q000628:therapy; D014481:United States / Q000453:epidemiology
keywords: Cancer; Euvolemic; Hypervolemic; Hyponatremia; Survival