Impact of continuous value of body mass index on graft loss in overweight patients.

INTRODUCTION

High body mass index (BMI) is associated with increased cardiovascular mortality and risk of progression to end-stage renal disease both among the general population and among renal transplant patients. However, in the latter condition no unequivocal studies have been reported in the literature. The aim of our study was to investigate continuous versus categorical values of BMI (World Health Organization classification) as an independent risk factor in renal transplantation.

PATIENTS AND METHODS

We retrospectively studied 194 renal transplant patients (128 males and 66 females) whose mean age at transplant was 43.9 years. They had 5 years follow-up. To investigate the association between BMI and graft survival, we performed univariate and multivariate analyses using the Cox regression model. This model was adjusted both for classical covariates (age, gender, time on dialysis, HLA mismatches, donor status) and other covariates as delayed graft function (DGF), acute rejection episodes (AR), and chronic allograft nephropathy (CAN), which are universally recognized to be predictors of graft loss as evidenced by a need for dialysis treatments.

RESULTS

At the time of transplantation, the BMI averaged 24.4 +/- 2.65 kg/m(2). Upon univariate analysis, age (P = .049), BMI (P = .005), DGF (P = .009), ARE (P < .0001), and CAN (P = .001) were significantly related to poor transplant outcomes. Upon multivariate analysis, only the BMI value, considered as continuous value (P = .013), DGF (P = .030), and ARE (P < .0001) were significantly related to graft loss.

CONCLUSIONS

BMI as a continuous value represented an independent risk factor for renal transplant loss at 5 years. Correction of pretransplant body weight both in overweight (25 <or= BMI <or= 30) and normal-weight patients is essential to avoid graft loss.