title: Urine Potassium Excretion, Kidney Failure, and Mortality in CKD.
abstract: BACKGROUND
  Low urine potassium excretion, as a surrogate for dietary potassium intake, is associated with higher risk for hypertension and cardiovascular disease in a general population. Few studies have investigated the relationship of urine potassium with clinical outcomes in chronic kidney disease (CKD).
  
  
  METHODS
  Longitudinal cohort study.
  
  
  METHODS
  The MDRD (Modification of Diet in Renal Disease) Study was a randomized controlled trial (N = 840) conducted in 1989 to 1993 to examine the effects of blood pressure control and dietary protein restriction on kidney disease progression in adults aged 18 to 70 years with CKD stages 2 to 4. This post hoc analysis included 812 participants.
  
  
  METHODS
  The primary predictor variable was 24-hour urine potassium excretion, measured at baseline and at multiple time points (presented as time-updated average urine potassium excretion).
  
  
  RESULTS
  Kidney failure, defined as initiation of dialysis therapy or transplantation, was determined from US Renal Data System data. All-cause mortality was assessed using the National Death Index.
  
  
  RESULTS
  Median follow-up for kidney failure was 6.1 (IQR, 3.5-11.7) years, with 9 events/100 patient-years. Median all-cause mortality follow-up was 19.2 (IQR, 10.8-20.6) years, with 3 deaths/100 patient-years. Baseline mean urine potassium excretion was 2.39±0.89 (SD) g/d. Each 1-SD higher baseline urine potassium level was associated with an adjusted HR of 0.95 (95% CI, 0.87-1.04) for kidney failure and 0.83 (95% CI, 0.74-0.94) for all-cause mortality. Results were consistent using time-updated average urine potassium measurements.
  
  
  CONCLUSIONS
  Analyses were performed using urine potassium excretion as a surrogate for dietary potassium intake. Results are obtained from a primarily young, nondiabetic, and advanced CKD population and may not be generalizable to the general CKD population.
  
  
  CONCLUSIONS
  Higher urine potassium excretion was associated with lower risk for all-cause mortality, but not kidney failure.
authors.affiliation: Division of Nephrology, Department of Medicine, Tufts Medical Center, Boston, MA.
authors.forename: Amanda K
authors.initials: AK
authors.lastname: Leonberg-Yoo
authors.affiliation: Research Design Center/Biostatistics Research Center, Tufts CTSI and Institute for Clinical Research and Health Policy Studies, Tufts Medical Center, Boston, MA.
authors.forename: Hocine
authors.initials: H
authors.lastname: Tighiouart
authors.affiliation: Division of Nephrology, Department of Medicine, Tufts Medical Center, Boston, MA.
authors.forename: Andrew S
authors.initials: AS
authors.lastname: Levey
authors.affiliation: Department of Quantitative Health Sciences, Cleveland Clinic, Cleveland, OH.
authors.forename: Gerald J
authors.initials: GJ
authors.lastname: Beck
authors.affiliation: Division of Nephrology, Department of Medicine, Tufts Medical Center, Boston, MA. Electronic address: msarnak@tuftsmedicalcenter.org.
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Sarnak
mesh_terms: D015331:Cohort Studies; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D011188:Potassium / Q000652:urine*; D051437:Renal Insufficiency / Q000209:etiology; D051436:Renal Insufficiency, Chronic / Q000150:complications / Q000401:mortality* / Q000503:physiopathology / Q000652:urine*
chemical_list: D011188:Potassium
keywords: Urine potassium; all-cause mortality; chronic kidney disease (CKD); dietary potassium intake; end-stage renal disease (ESRD); kidney failure; modifiable risk factor; potassium excretion