title: Serum Magnesium and Mortality in Hemodialysis Patients in the United States: A Cohort Study.
abstract: BACKGROUND
  Low serum magnesium levels in patients with kidney disease have been linked to increased mortality. This study investigated whether similar associations existed in maintenance hemodialysis (HD) patients.
  
  
  METHODS
  Cohort study.
  
  
  METHODS
  All Fresenius Medical Care North America in-center HD patients with available serum magnesium measurements were studied. The initial exploratory study in 21,534 HD patients evaluated associations among serum magnesium level, dialysate magnesium concentration, and mortality from April 2007 through June 2008. The follow-up study in 27,544 HD patients evaluated associations between serum magnesium levels and mortality over 1 year (January through December 2008).
  
  
  METHODS
  The primary predictor was serum magnesium level, with adjustment for case-mix (age, sex, race, diabetes, and dialysis vintage and additionally for follow-up study: body surface area and vascular access) and laboratory variables (albumin, hemoglobin, phosphorus, equilibrated Kt/V, potassium, calcium, and intact parathyroid hormone values).
  
  
  RESULTS
  Primary outcome variable was 1-year mortality risk, evaluated using Cox proportional hazards models.
  
  
  RESULTS
  Among 21,534 HD patients in the exploratory study, there were 3,682 deaths. Higher dialysate magnesium level was associated with higher serum magnesium level (R=0.22; P<0.001). Patients with the lowest serum magnesium levels (<1.30 mEq/L) were at highest risk for death (HR, 1.63; 95% CI, 1.30-1.96; reference serum magnesium, 1.60-<1.90 mEq/L). Among 27,544 HD patients in the follow-up study, there were 4,531 deaths. In Cox proportional hazards models, there was a linear decline in death risk from the lowest to the highest serum magnesium category, with the best survival at serum magnesium levels ≥ 2.50 mEq/L (HR, 0.68; 95% CI, 0.56-0.82). However, risk estimates were attenuated with case-mix and lab adjustment. This pattern was consistent within diabetes subgroups and for cardiovascular or noncardiovascular causes of death.
  
  
  CONCLUSIONS
  Observational study with cross-sectional serum magnesium measurements and no information for oral magnesium intake.
  
  
  CONCLUSIONS
  Elevated serum magnesium levels > 2.10 mEq/L were associated with better survival than low serum magnesium levels < 1.30 mEq/L in HD patients. Prospective studies may determine whether manipulation of low serum magnesium levels affects survival.
authors.affiliation: Fresenius Medical Care North America, Waltham, MA. Electronic address: nephdoc92@gmail.com.
authors.forename: Eduardo
authors.initials: E
authors.lastname: Lacson
authors.affiliation: Alcon Laboratories, Fort Worth, TX.
authors.forename: Weiling
authors.initials: W
authors.lastname: Wang
authors.affiliation: Fresenius Medical Care North America, Waltham, MA.
authors.forename: Lin
authors.initials: L
authors.lastname: Ma
authors.affiliation: Department of Nephrology, University of Duesseldorf, Duesseldorf, Germany.
authors.forename: Jutta
authors.initials: J
authors.lastname: Passlick-Deetjen
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007676:Kidney Failure, Chronic / Q000097:blood* / Q000175:diagnosis / Q000401:mortality*; D008274:Magnesium / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009026:Mortality / Q000639:trends; D006435:Renal Dialysis / Q000009:adverse effects / Q000401:mortality*; D012189:Retrospective Studies; D014481:United States / Q000453:epidemiology
chemical_list: D015415:Biomarkers; D008274:Magnesium
keywords: Serum magnesium concentration; dialysate magnesium prescription; end-stage renal disease (ESRD); hemodialysis (HD); hypermagnesemia; hypomagnesemia; mortality risk