title: Vitamin D deficiency is associated with mortality and adverse vascular access outcomes in patients with end-stage renal disease.
abstract: BACKGROUND
  Plasma 25 hydroxycholecalciferol (vitamin D) deficiency has been associated with adverse cardiovascular outcomes in epidemiologic studies. Chronic kidney disease is associated with loss of 1α-hydroxylase and consequently vitamin D deficiency. We hypothesized that vitamin D deficiency was associated with increased mortality and increased vascular access failure in patients undergoing permanent vascular access for end-stage renal disease.
  
  
  METHODS
  This retrospective cohort study analyzed 128 patients undergoing permanent vascular access surgery between 2003 and 2012 for whom concurrent plasma vitamin D levels were also available. Levels were considered deficient at <20 ng/mL. Multivariable analysis was used to determine the association between vitamin D and mortality and vascular access outcomes.
  
  
  RESULTS
  The mean age was 66.7 years, 96.8% were male, 32.0% were African American, and 60.9% had diabetes mellitus. In the entire cohort, 55.5% were vitamin D-deficient, despite similar rates of repletion among the vitamin D-deficient and nondeficient groups. During a median follow-up of 2.73 years, there were 40 deaths (31%). Vitamin D-deficient patients tended to be younger (P = .01) and to have higher total cholesterol (P = .001) and lower albumin (P = .017) and calcium (P = .007) levels. Despite their younger age, mortality was significantly higher (P = .026) and vascular access failure was increased (P = .008) in the vitamin D-deficient group. Multivariate logistic regression analysis found vitamin D deficiency (odds ratio [OR], 3.64; 95% confidence interval [CI], 1.12-11.79; P = .031), hemodialysis through a central catheter (OR, 3.08; 95% CI, 1.04-9.12; P = .042), coronary artery disease (OR, 3.08; 95% CI, 1.06-8.94; P = .039), increased age (OR, 1.09; 95% CI, 1.03-1.15; P = .001), and albumin (OR, 0.27; 95% CI, 0.09-0.83; P = .023) remained independent predictors of mortality. Vitamin D deficiency (hazard ratio [HR], 2.34; 95% CI, 1.17-4.71; P = .02), a synthetic graft (HR, 3.50; 95% CI, 1.38-8.89; P = .009), and hyperlipidemia (HR, 0.42; 95% CI, 0.22-0.81; P = .01) were independent predictors of vascular access failure in a Cox proportional hazard model.
  
  
  CONCLUSIONS
  Vitamin D deficiency is highly prevalent in patients undergoing vascular access procedures. Patients who are deficient in vitamin D have worse survival and worse vascular access outcomes. Further study is warranted to assess whether aggressive vitamin D repletion will improve outcomes in this population.
authors.affiliation: Department of Vascular and Endovascular Surgery, University of California, San Francisco, San Francisco, Calif. Electronic address: joy.walker@ucsfmedctr.org.
authors.forename: Joy P
authors.initials: JP
authors.lastname: Walker
authors.affiliation: Department of Vascular and Endovascular Surgery, University of California, San Francisco, San Francisco, Calif.
authors.forename: Jade S
authors.initials: JS
authors.lastname: Hiramoto
authors.affiliation: Department of Vascular and Endovascular Surgery, University of California, San Francisco, San Francisco, Calif.
authors.forename: Warren J
authors.initials: WJ
authors.lastname: Gasper
authors.affiliation: Case Western Reserve University, Cleveland, Ohio.
authors.forename: Philip
authors.initials: P
authors.lastname: Auyang
authors.affiliation: Department of Vascular and Endovascular Surgery, University of California, San Francisco, San Francisco, Calif.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Conte
authors.affiliation: Department of Vascular and Endovascular Surgery, University of California, San Francisco, San Francisco, Calif.
authors.forename: Joseph H
authors.initials: JH
authors.lastname: Rapp
authors.affiliation: Department of Vascular Surgery, San Francisco Veteran's Administration Medical Center, San Francisco, Calif.
authors.forename: David H
authors.initials: DH
authors.lastname: Lovett
authors.affiliation: Department of Vascular and Endovascular Surgery, University of California, San Francisco, San Francisco, Calif.
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Owens
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001166:Arteriovenous Shunt, Surgical / Q000009:adverse effects*; D001807:Blood Vessel Prosthesis / Q000009:adverse effects; D002112:Calcifediol / Q000097:blood / Q000172:deficiency*; D002118:Calcium / Q000097:blood; D002405:Catheterization, Central Venous; D002784:Cholesterol / Q000097:blood; D003327:Coronary Disease / Q000453:epidemiology; D005500:Follow-Up Studies; D006801:Humans; D006949:Hyperlipidemias / Q000453:epidemiology; D053208:Kaplan-Meier Estimate; D007676:Kidney Failure, Chronic / Q000150:complications / Q000401:mortality* / Q000628:therapy; D008875:Middle Aged; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D012307:Risk Factors; D012709:Serum Albumin / Q000378:metabolism; D014808:Vitamin D Deficiency / Q000097:blood / Q000150:complications / Q000401:mortality*
chemical_list: D012709:Serum Albumin; D002784:Cholesterol; D002112:Calcifediol; D002118:Calcium