title: Bone alkaline phosphatase and mortality in dialysis patients.
abstract: OBJECTIVE
  Serum alkaline phosphatase (AP) is associated with vascular calcification and mortality in hemodialysis patients, but AP derives from various tissues of origin. The aim of this study was to assess the effect of bone-specific AP (BAP) on morbidity and mortality in dialysis patients.
  
  
  METHODS
  From a prospective cohort study of incident dialysis patients in The Netherlands, all patients with measured BAP at 12 months after the start of dialysis (baseline) were included in the analysis (n = 800; mean age, 59 ± 15 years; mean BAP = 18 ± 13 U/L). By Cox regression analyses, we assessed the impact of BAP levels on short-term mortality (6 months) and longer-term mortality (4-year follow-up).
  
  
  RESULTS
  High levels of BAP strongly affected short-term mortality. After adjustment for confounders, patients in the highest BAP tertile had a 5.7-fold increased risk of death within 6 months compared with patients in the lowest tertile. The effect applied to both cardiovascular and noncardiovascular mortality. Furthermore, high levels of BAP were associated with increased cardiovascular mortality in the longer term. In comparison with total AP, the effect sizes related to clinical outcomes were much higher for BAP.
  
  
  CONCLUSIONS
  High levels of BAP were strongly associated with short-term mortality in dialysis patients, pointing out the important impact of bone turnover. Longitudinal assessments of BAP may be useful for the treatment monitoring in clinical practice in dialysis patients.
authors: Department of Clinical Epidemiology, Leiden University Medical Center, Leiden, The Netherlands. c.drechsler@gmx.net
authors: Christiane
authors: C
authors: Drechsler
authors: Marion
authors: M
authors: Verduijn
authors: Stefan
authors: S
authors: Pilz
authors: Raymond T
authors: RT
authors: Krediet
authors: Friedo W
authors: FW
authors: Dekker
authors: Christoph
authors: C
authors: Wanner
authors: Markus
authors: M
authors: Ketteler
authors: Elisabeth W
authors: EW
authors: Boeschoten
authors: Vincent
authors: V
authors: Brandenburg