title: Haemoglobin variability in the early post-transplant period: association with graft survival and mortality.
abstract: OBJECTIVE
  Haemoglobin (Hb) variability is associated with poor survival in patients with chronic kidney disease. Association of Hb variability after kidney transplantation with patients' and graft survival has not been adequetly studied.
  
  
  METHODS
  This retrospective study used registry data to examine the association between Hb variability in the early post-transplant period (first 6 months) and graft survival after kidney transplantatin. Kaplan-Meier and Cox regression analyses were used for univariate and multivariate associations between mortality, death censored graft survival and the composite outcome of both, in 752 patients after kidney transplantation. Hb values were collected each month during the first 6 months after transplantation, and Hb variavility was calculated using the residual standard deviation method.
  
  
  RESULTS
  The highest quartile of Hb variability was associated with inferior graft and patients' survival in univariate (hazard ratio (HR) 2.18; 95% confidence interval (CI) 1.51 to 3.13; P < 0.001) and multivariate models (HR 1.5; 95% CI 1.029 to 2.18; P = 0.035). This association was mainly due to increased death censored graft failure in the high variability group (HR 2.75; 95% CI 1.73 to 4.38; P < 0.001) and (HR 1.67; 95% CI 1.023 to 2.74; P = 0.04) in the univariate and multivariate models, respectively. There was no association between Hb variability and the risk of death (HR 1.51; 95% CI 0.88 to 2.57; P = 0.132).
  
  
  CONCLUSIONS
  High Hb variability is independently associated with inferior graft survival in patients after kidney transplantation.
authors.affiliation: Nephrology and Hypertension, Rabin Medical Center, Petah Tikva, Israel. benayarz@gmail.com
authors.forename: Benaya
authors.initials: B
authors.lastname: Rozen-Zvi
authors.forename: Binjamin
authors.initials: B
authors.lastname: Ben-Avraham
authors.forename: Shira
authors.initials: S
authors.lastname: Schneider
authors.forename: Anat
authors.initials: A
authors.lastname: Gafter-Gvili
authors.forename: Rachel S
authors.initials: RS
authors.lastname: Levy-Drummer
authors.forename: Boris
authors.initials: B
authors.lastname: Zingerman
authors.forename: Eitan
authors.initials: E
authors.lastname: Mor
authors.forename: Uzi
authors.initials: U
authors.lastname: Gafter
authors.forename: Ruth
authors.initials: R
authors.lastname: Rahamimov
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D016009:Chi-Square Distribution; D006085:Graft Survival; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D053208:Kaplan-Meier Estimate; D016030:Kidney Transplantation / Q000009:adverse effects / Q000401:mortality*; D015999:Multivariate Analysis; D016016:Proportional Hazards Models; D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D015415:Biomarkers; D006454:Hemoglobins