title: Low 25-hydroxyvitamin D levels and mortality in non-dialysis-dependent CKD.
abstract: BACKGROUND
  Low 25-hydroxyvitamin D (25[OH]D) levels are common in patients with non-dialysis-dependent chronic kidney disease (CKD). The associations between low 25(OH)D levels and mortality in non-dialysis-dependent patients with CKD are unclear.
  
  
  METHODS
  Retrospective cohort study.
  
  
  METHODS
  Patients with stages 3-4 CKD (estimated glomerular filtration rate, 15-59 mL/min/1.73 m(2); n = 12,673) who had 25(OH)D levels measured after the diagnosis of CKD in the Cleveland Clinic Health System.
  
  
  METHODS
  25(OH)D levels categorized into 3 groups: <15, 15-29, and ≥30 ng/mL.
  
  
  RESULTS
  We examined factors associated with low 25(OH)D levels and associations between low 25(OH)D levels and all-cause mortality (ascertained using the Social Security Death Index and our electronic medical record) using logistic regression, Cox proportional hazard models, and Kaplan-Meier survival curves.
  
  
  METHODS
  25(OH)D was measured using chemiluminescence immunoassay.
  
  
  RESULTS
  Of 12,763 patients with CKD, 15% (n = 1,970) had 25(OH)D levels <15 ng/mL, whereas 45% (n = 5,749) had 25(OH)D levels of 15-29 ng/mL. Male sex, African American race, diabetes, coronary artery disease, and lower estimated glomerular filtration rate were associated significantly with 25(OH)D level <30 ng/mL. A graded increase in risk of 25(OH)D level <30 ng/mL was evident across increasing body mass index levels. Patients who had 25(OH)D levels measured in fall through spring had higher odds for 25(OH)D levels <30 ng/mL. After covariate adjustment, patients with CKD with 25(OH)D levels <15 ng/mL had a 33% increased risk of mortality (95% CI, 1.07-1.65). The group with 25(OH)D levels of 15-29 ng/mL did not show a significantly increased risk of mortality (HR, 1.03; 95% CI, 0.86-1.22) compared with patients with 25(OH)D levels ≥30 ng/mL.
  
  
  CONCLUSIONS
  Single-center observational study, lack of data for albuminuria and other markers of bone and mineral disorders, and attrition bias.
  
  
  CONCLUSIONS
  25(OH)D level <15 ng/mL was associated independently with all-cause mortality in non-dialysis-dependent patients with CKD.
authors.affiliation: Department of Nephrology and Hypertension, Glickman Urological and Kidney Institute, Cleveland, OH 44195, USA. navanes@ccf.org
authors.forename: Sankar D
authors.initials: SD
authors.lastname: Navaneethan
authors.forename: Jesse D
authors.initials: JD
authors.lastname: Schold
authors.forename: Susana
authors.initials: S
authors.lastname: Arrigain
authors.forename: Stacey E
authors.initials: SE
authors.lastname: Jolly
authors.forename: Anil
authors.initials: A
authors.lastname: Jain
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Schreiber
authors.forename: James F
authors.initials: JF
authors.lastname: Simon
authors.forename: Titte R
authors.initials: TR
authors.lastname: Srinivas
authors.forename: Joseph V
authors.initials: JV
authors.lastname: Nally
mesh_terms: D001741:Black or African American / Q000706:statistics & numerical data; D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D002423:Cause of Death; D016009:Chi-Square Distribution; D002908:Chronic Disease; D015897:Comorbidity; D003928:Diabetic Nephropathies / Q000097:blood / Q000401:mortality; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D007674:Kidney Diseases / Q000097:blood* / Q000401:mortality*; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D016016:Proportional Hazards Models; D012042:Registries; D012621:Seasons; D014481:United States / Q000453:epidemiology; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000453:epidemiology*
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D