Introduction: The impact of obesity defined by a body mass index [BMI] > 30 kg/m[sup2] on kidney allograft outcomes remains controversial. The use of BMI to assess obesity has been challenged in recent years: higher BMI reflects both increased visceral/subcutaneous fat and muscle mass. The use of waist circumference (WC) seems to be more appropriate to evaluate abdominal obesity. However, data evaluating the impact of higher waist circumference on kidney allograft outcomes are lacking. The aim of this study was to assess the impact of both BMI and WC on graft survival and mortality.

Methods: This is a monocentric prospective cohort study including all transplant recipients for whom anthropometric characteristics (BMI+/-WC) were recorded at 3 +/-1 months after kidney transplantation and with a functioning graft more than one year between 1996 and 2010 in Montpellier University Hospital (France). In order to evaluate the effects of BMI and WC on graft outcomes, kidney recipients were divided into 4 groups of BMI according to WHO recommendations and into 4 groups of WC according to values of quartiles stratified for sex. Cox models were used to analyze patients and death censored graft survival.

Results: We included 762 renal transplant recipients (age 45.28+/-16.46 years, 57 % men); 53 recipients had a BMI> 30 kg/m[sup2] at 3 months post-transplant. During follow up of 123.7 +/- 48.26 months, 79 recipients died and 136 lost their graft. Patients with higher BMI and higher WC were significantly older, had more arterial hypertension. They presented more delayed graft function, their graft function was lower at 3 months. In univariate and multivariate analysis, a BMI ≥ 30 kg/m[sup2] was not a risk factor for death-censored graft failure and mortality. By contrast, higher WC (>98 cm in men, <90 cm in women) was an independent risk factor for graft loss (Hazard Ratio: 7.41 – confidence interval 95% [2.64- 21.57]; p=0.001), but had no impact on mortality.

Conclusion: In our cohort, BMI had no impact on graft outcomes whereas higher WC was an independent risk factor for graft failure but not for mortality. WC appears to be a better prognostic marker for obesity than BMI.

CITATION INFORMATION: Serre J.-E, Huet M, Scwarc I, Pernin V, Le Quintrec M, Mourad G. Impact of Body Mass Index and Waist Circumference in Kidney Transplant Recipients. Am J Transplant. 2017;17 (suppl 3).

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