title: Hypokalemia in acute medical patients: risk factors and prognosis.
abstract: OBJECTIVE
  Hypokalemia is one of the most common electrolyte disorders in hospitalized patients. It is associated with a high mortality rate among patients with cardiovascular disease. Whether hypokalemia confers a similar risk in an unselected hospitalized population is not well established.
  
  
  METHODS
  We conducted a prospective cohort study involving all first-time admissions (n = 11,988) to the Acute Medical Department at Odense University Hospital linking potassium level at admission with registry data on patient characteristics, laboratory data, redeemed prescriptions, and time of death for the period from August 2009 to August 2011. We estimated hazard ratios for all-cause mortality within 0 to 7 days and 8 to 30 days after admission, comparing patients with hypokalemia at admission (plasma [K(+)] level <3.4 mmol/L) with patients with eukalemia at admission ([K(+)] level of 3.4-3.8 mmol/L).
  
  
  RESULTS
  Hypokalemia occurred in 16.8% of first-time admissions (n = 2011). It was associated with an adjusted hazard ratio [HR] of 1.34 (95% confidence interval [CI], 0.98-1.85) for 7-day mortality and 1.56 (95% CI, 1.18-3.06) for 8- to 30-day mortality. Among patients with more severe hypokalemia (plasma [K(+)] <2.9 mmol/L), the adjusted HR was 2.17 (95% CI, 1.34-3.49) for 7-day mortality and 1.90 (95% CI, 1.18-3.06) for 8- to 30-day mortality. Prognostic factors for both 7-day and 8- to 30-day mortality among hypokalemic patients were increasing age and Charlson Comorbidity Index, whereas there was no prognostic effect of current diuretic or beta-agonist use.
  
  
  CONCLUSIONS
  In a mixed population of hospitalized medical patients, hypokalemia is common, and plasma [K(+)] <2.9 mmol/L is associated with increased 7-day and 8- to 30-day mortality.
authors.affiliation: Department of Emergency Medicine, Odense University Hospital, Denmark. Electronic address: Helene.Jensen@rsyd.dk.
authors.forename: Helene Kildegaard
authors.initials: HK
authors.lastname: Jensen
authors.affiliation: Department of Medicine, Sydvestjysk Sygehus Esbjerg, Denmark.
authors.forename: Mikkel
authors.initials: M
authors.lastname: Brabrand
authors.affiliation: Department of Clinical Biochemistry and Pharmacology, Odense University Hospital, Denmark.
authors.forename: Pernille Just
authors.initials: PJ
authors.lastname: Vinholt
authors.affiliation: Clinical Pharmacology, Institute of Public Health, University of Southern Denmark, Denmark.
authors.forename: Jesper
authors.initials: J
authors.lastname: Hallas
authors.affiliation: Department of Emergency Medicine, Odense University Hospital, Denmark.
authors.forename: Annmarie Touborg
authors.initials: AT
authors.lastname: Lassen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003718:Denmark / Q000453:epidemiology; D005260:Female; D006801:Humans; D007008:Hypokalemia / Q000209:etiology / Q000401:mortality*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D014505:Urban Population / Q000706:statistics & numerical data
keywords: Comorbidity; Diuretics; Electrolytes; Hospitalization; Hypokalemia; Medications; Mortality; Potassium