Obesity and Outcome Following Renal Transplantation

Abstract

Single institution series have demonstrated that obese patients have higher rates of wound infection and delayed graft function (DGF), but similar rates of graft survival. We used UNOS data to determine whether obesity affects outcome following renal transplantation.From the UNOS database, we identified patients who underwent primary kidney-only transplantation between 1997 and 1999. Recipient and donor body mass index (BMI) was categorized as underweight (BMI < 18.5), normal (BMI 18.5-24.9), overweight (BMI 25-29.9), obese (BMI 30-34.9) or morbidly obese (BMI ≥ 35). We correlated BMI with intermediate measures of graft outcome and overall graft survival, and created multivariate models to evaluate the independent effect of BMI on graft outcome, adjusting for factors known to affect graft success.The study sample comprised 27 377 recipients. Older age, female sex, African American race and increased comorbidity were associated with obesity (p < 0.001). Compared with normal weight patients, morbid obesity was independently associated with an increased risk of DGF (p < 0.001), prolonged hospitalization (p < 0.001), acute rejection (p = 0.006) and decreased overall graft survival (p = 0.001). Donor BMI did not affect overall graft survival (p ≥ 0.07).Recipient obesity is associated with an increased risk of DGF and decreased graft survival following renal transplantation.

Obesity and Kidney Transplantation

“…In a large study which included 51,927 kidney transplant recipients, severe obesity (BMI > 35 kg/m 2 ) was associated with a 51% increased risk of DGF compared to the transplant recipients with a BMI between 22-24 kg/m 2 (41). These findings were supported by a study which included data from 27,377 kidney transplant recipients (40). Overall mortality, regardless of obesity status, is substantially reduced with kidney transplantation (43,44).…”

“…Obese kidney transplant recipients are at increased risk for short-term complications including delayed wound healing, longer surgical times, and delayed graft function (39,40). Data on whether obese transplant recipients are at higher risk for long-term adverse outcomes remains controversial, but the majority of larger studies suggest poorer long-term outcomes among obese individuals compared to non-obese individuals (40)(41)(42). The decision by some transplant centers to use BMI thresholds for the exclusion of patients from kidney transplantation should consider both societal and individual level concerns.…”

“…However, compared to non-obese kidney transplant recipients, obese transplant recipients appear to have an increased risk of graft loss although not all studies agree (39)(40)(41)(42)(43)(44)(45)(46)(47)(48)(49)(50)(51)(52)(53)(54)(55)(56) (40,41). The magnitude of the association between morbid obesity and graft failure is similar to the increased risk of graft failure associated with diabetes (40). Overall mortality after kidney transplantation does not appear to be associated with obesity itself.…”

Paediatric obesity and renal transplantation: current challenges and solutions

“…Adult studies report widely on the strong association between delayed graft function and obesity [17][18][19][20][21][22]. Some of the reasons for this association may relate to the technical challenges at the time of surgery, including a prolonged anastomotic time leading to longer warm ischaemia duration, whilst others may be related to the type of donor (donation after circulatory death) or the negative impact of higher calcineurin inhibitor doses.…”

“…In the adult population, there is conflicting evidence as to whether obesity is related to a higher incidence of acute rejection [19,[25][26][27][28]. The available paediatric evidence appears to suggest a similar experience, with little difference in the rate of acute rejection between obese and non-obese patients.…”