title: Development of severe hyponatraemia in hospitalized patients: treatment-related risk factors and inadequate management.
abstract: BACKGROUND
  Although hyponatraemia [plasma sodium (PNa)<136 mmol/l] frequently develops in hospital, risk factors for hospital-acquired hyponatraemia remain unclear.
  
  
  METHODS
  Patients who presented with severe hyponatraemia (PNa<or=125 mmol/l) were compared with patients with hospital-acquired severe hyponatraemia in a 3 month hospital-wide cohort study.
  
  
  RESULTS
  Thirty-eight patients had severe hyponatraemia on admission (PNa 121+/-4 mmol/l), whereas 36 patients had hospital-acquired severe hyponatraemia (PNa 133+/-5-->122+/-4 mmol/l). In hospital-acquired hyponatraemia, treatment started significantly later (1.0+/-2.6 vs 9.8+/-10.6 days, P<0.001) and the duration of hospitalization was longer (18.2+/-11.5 vs 30.7+/-23.4 days, P=0.01). The correction of PNa in hospital-acquired hyponatraemia was slower after both 24 h (6+/-4 vs 4+/-4 mmol/l, P=0.009) and 48 h (10+/-6 mmol/l vs 6+/-5 mmol/l, P=0.001) of treatment. Nineteen patients (26%) from both groups were not treated for hyponatraemia and this was associated with a higher mortality rate (seven out of 19 vs seven out of 55, P=0.04). Factors that contributed to hospital-acquired hyponatraemia included: thiazide diuretics (none out of 38 vs eight out of 36, P=0.002), drugs stimulating antidiuretic hormone (two out of 38 vs eight out of 36, P=0.04), surgery (none out of 38 vs 10 out of 36, P<0.001) and hypotonic intravenous fluids (one out of 38 vs eight out of 36, P=0.01). Symptomatic hyponatraemia was present in 27 patients (36%), and 14 patients died (19%).
  
  
  CONCLUSIONS
  The development of severe hyponatraemia in hospitalized patients was associated with treatment-related factors and inadequate management. Early recognition of risk factors and expedited therapy may make hospital-acquired severe hyponatraemia more preventable.
authors.affiliation: Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands.
authors.forename: Ewout J
authors.initials: EJ
authors.lastname: Hoorn
authors.forename: Jan
authors.initials: J
authors.lastname: Lindemans
authors.forename: Robert
authors.initials: R
authors.lastname: Zietse
mesh_terms: D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D006760:Hospitalization; D006785:Hospitals, University; D006801:Humans; D007010:Hyponatremia / Q000453:epidemiology* / Q000209:etiology* / Q000503:physiopathology; D007049:Iatrogenic Disease; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D018570:Risk Assessment; D012720:Severity of Illness Index; D017678:Sex Distribution; D049993:Sodium Chloride Symporter Inhibitors / Q000009:adverse effects*; D015996:Survival Rate
chemical_list: D049993:Sodium Chloride Symporter Inhibitors