title: Prevalence of hypokalemia before and after bowel preparation for colonoscopy in high-risk patients.
abstract: OBJECTIVE
  Bowel preparation for colonoscopy should not cause significant shifts in systemic electrolyte concentrations. We recently encountered 2 cases of severe postcolonoscopy hypokalemia with fatal consequences, prompting us to conduct a study to explore the magnitude of and risk factors for hypokalemia associated with bowel preparation. We paid specific attention to higher-risk subgroups, in particular, diuretic users, hospitalized patients, and patients estimated to be at high risk by the gastroenterologist.
  
  
  METHODS
  From January 1 to December 31, 2014, we included all patients at risk for hypokalemia (diuretic users, hospitalized patients, and patients estimated at high risk by the gastroenterologist) who underwent colonoscopy at our institution. We measured serum potassium levels before low-volume polyethylene glycol bowel preparation for colonoscopy. In a subset of patients who had normal serum potassium levels before bowel cleansing, serum potassium levels after bowel cleansing also were measured.
  
  
  RESULTS
  In total, 5515 colonoscopies were performed, including 1822 procedures in diuretic users or hospitalized patients. Of these, 77 (4.2%) patients had hypokalemia before bowel cleansing. A logistic regression model showed that hospitalized patients were more likely to have hypokalemia than non-hospitalized patients. 301 patients with normal potassium levels had potassium controls after bowel cleansing, of whom 71 (23.6%) developed hypokalemia. A logistic regression model showed that diuretic users were more likely to develop hypokalemia than those who did not use diuretics.
  
  
  CONCLUSIONS
  Hypokalemia is frequently encountered after low-volume polyethylene glycol bowel cleansing in high-risk patients. Additional large-scale studies are needed on the prevalence of hypokalemia in unselected populations undergoing bowel cleansing and on the occurrence of potentially very serious side effects in order to decide on screening of high-risk groups in daily clinical practice. (Clinical trial registration number: NTR5400.).
authors.affiliation: Department of Internal Medicine and Gastroenterology, Zuyderland Medical Center, Heerlen, the Netherlands; Division of Gastroenterology and Hepatology, Department of Internal Medicine, Maastricht University Medical Center, Maastricht, the Netherlands; NUTRIM, School for Nutrition, Toxicology and Metabolism, Maastricht University, Maastricht, the Netherlands.
authors.forename: Ankie
authors.initials: A
authors.lastname: Reumkens
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Internal Medicine, Maastricht University Medical Center, Maastricht, the Netherlands; NUTRIM, School for Nutrition, Toxicology and Metabolism, Maastricht University, Maastricht, the Netherlands.
authors.forename: Ad A
authors.initials: AA
authors.lastname: Masclee
authors.affiliation: Department of Methodology and Statistics, Maastricht University, Maastricht, the Netherlands; CAPHRI, School for Public Health and Primary Care, Maastricht University, Maastricht, the Netherlands.
authors.forename: Bjorn
authors.initials: B
authors.lastname: Winkens
authors.affiliation: Department of Internal Medicine and Gastroenterology, Zuyderland Medical Center, Heerlen, the Netherlands; Division of Gastroenterology and Hepatology, Department of Internal Medicine, Maastricht University Medical Center, Maastricht, the Netherlands.
authors.forename: Cees T
authors.initials: CT
authors.lastname: van Deursen
authors.affiliation: Division of Gastroenterology and Hepatology, Department of Internal Medicine, Maastricht University Medical Center, Maastricht, the Netherlands; GROW, School for Oncology and Developmental Biology, Maastricht University, Maastricht the Netherlands.
authors.forename: Silvia
authors.initials: S
authors.lastname: Sanduleanu
authors.affiliation: Department of Internal Medicine and Gastroenterology, Zuyderland Medical Center, Heerlen, the Netherlands.
authors.forename: Christine M
authors.initials: CM
authors.lastname: Bakker
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002400:Cathartics / Q000009:adverse effects*; D003113:Colonoscopy / Q000379:methods*; D004232:Diuretics / Q000627:therapeutic use*; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D007008:Hypokalemia / Q000139:chemically induced / Q000453:epidemiology*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011092:Polyethylene Glycols / Q000009:adverse effects*; D011300:Preoperative Care / Q000009:adverse effects*; D015995:Prevalence; D012306:Risk; D012307:Risk Factors; D055815:Young Adult
chemical_list: D002400:Cathartics; D004232:Diuretics; D011092:Polyethylene Glycols