Haemoglobin variability in the early post-transplant period: association with graft survival and mortality.

AIM: 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). CONCLUSION: High Hb variability is independently associated with inferior graft survival in patients after kidney transplantation.