title: Vitamin D status and its association with season, hospital and sepsis mortality in critical illness.
abstract: BACKGROUND
  Vitamin D plays a key role in immune function. Deficiency may aggravate the incidence and outcome of infectious complications in critically ill patients. We aimed to evaluate the prevalence of vitamin D deficiency and the correlation between serum 25-hydroxyvitamin D (25(OH) D) and hospital mortality, sepsis mortality and blood culture positivity.
  
  
  METHODS
  In a single-center retrospective observational study at a tertiary care center in Graz, Austria, 655 surgical and nonsurgical critically ill patients with available 25(OH) D levels hospitalized between September 2008 and May 2010 were included. Cox regression analysis adjusted for age, gender, severity of illness, renal function and inflammatory status was performed. Vitamin D levels were categorized by month-specific tertiles (high, intermediate, low) to reflect seasonal variation of serum 25(OH) D levels.
  
  
  RESULTS
  Overall, the majority of patients were vitamin D deficient (<20 ng/ml; 60.2%) or insufficient (≥20 and <30 ng/dl; 26.3%), with normal 25(OH) D levels (>30 ng/ml) present in only 13.6%. The prevalence of vitamin D deficiency and mean 25(OH) D levels was significantly different in winter compared to summer months (P <0.001). Hospital mortality was 20.6% (135 of 655 patients). Adjusted hospital mortality was significantly higher in patients in the low (hazard ratio (HR) 2.05, 95% confidence interval (CI) 1.31 to 3.22) and intermediate (HR 1.92, 95% CI 1.21 to 3.06) compared to the high tertile. Sepsis was identified as cause of death in 20 of 135 deceased patients (14.8%). There was no significant association between 25(OH) D and C-reactive protein (CRP), leukocyte count or procalcitonin levels. In a subgroup analysis (n = 244), blood culture positivity rates did not differ between tertiles (23.1% versus 28.2% versus 17.1%, P = 0.361).
  
  
  CONCLUSIONS
  Low 25(OH) D status is significantly associated with mortality in the critically ill. Intervention studies are needed to investigate the effect of vitamin D substitution on mortality and sepsis rates in this population.
authors.forename: Karin
authors.initials: K
authors.lastname: Amrein
authors.forename: Paul
authors.initials: P
authors.lastname: Zajic
authors.forename: Christian
authors.initials: C
authors.lastname: Schnedl
authors.forename: Andreas
authors.initials: A
authors.lastname: Waltensdorfer
authors.forename: Sonja
authors.initials: S
authors.lastname: Fruhwald
authors.forename: Alexander
authors.initials: A
authors.lastname: Holl
authors.forename: Tadeja
authors.initials: T
authors.lastname: Purkart
authors.forename: Gerit
authors.initials: G
authors.lastname: Wünsch
authors.forename: Thomas
authors.initials: T
authors.lastname: Valentin
authors.forename: Andrea
authors.initials: A
authors.lastname: Grisold
authors.forename: Tatjana
authors.initials: T
authors.lastname: Stojakovic
authors.forename: Steven
authors.initials: S
authors.lastname: Amrein
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Pieber
authors.forename: Harald
authors.initials: H
authors.lastname: Dobnig
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D016638:Critical Illness / Q000401:mortality; D005260:Female; D017052:Hospital Mortality / Q000639:trends*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012621:Seasons; D018805:Sepsis / Q000097:blood* / Q000175:diagnosis / Q000401:mortality; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood; D014808:Vitamin D Deficiency / Q000097:blood* / Q000175:diagnosis / Q000401:mortality
chemical_list: D015415:Biomarkers; D014807:Vitamin D; C104450:25-hydroxyvitamin D