Is obesity still a risk factor in renal transplantation?

Abstract

At our center, since 1982, a body mass index (BMI) of less than 30 has been a prerequisite for placing a patient on the waiting list for renal transplantation. This decision was made because obese transplant recipients seemed to have a less than favorable post-transplant outcome. The aim of this study was to evaluate whether this requirement is still justified. Forty-six patients with a BMI above 30 underwent primary cadaveric renal transplantation between 1972 and 1993. For each of these obese patients, five consecutive nonobese (BMI 20-25) control patients were selected. Patient and graft survival, causes of graft loss, and acute rejection rate were evaluated for the two patient groups before and after the year 1982. Within the first 30 post-transplant days, one patient (2 Yo) and 11 grafts (24 Yo) were lost in the group of obese patients whereas seven patients (3 %) and 36 grafts (16 YO) were lost in the control group. Among the obese patients, renal circulatory complications were a major cause of graft loss. In the period 1973-1 981, the 1 -year patient survival rate was 65 O/O among obese patients versus 75 YO among controls from 1982 to 1993, this was 90 Yo versus 93 %. From 1973 to 1981, the 1-year graft survival rate was 25 YO among obese patients versus 53 YO among controls ( P < 0.05); from 1982 to 1993, it was 68 YO versus 84 YO ( P = NS). Multivariate analysis showed that the immunosuppressive regimen, age of the patient, BMI, and cold ischemia time of the graft had a significant influence on graft survival. The acute rejection rate within the first 30 days was 28 YO among obese patients and 35 YO among controls ( P = NS). We conclude that a BMI below or equal to 30 is still justified as a prerequisite for placement on the waiting list for renal transplantation, for despite an overall improvement, the outcome of renal transplantation in obese patients remains worse than that in non-obese patients.

Obesity is Associated with Worsening Cardiovascular Risk Factor Profiles and Proteinuria Progression in Renal Transplant Recipients

“…Although obesity has been associated with reduced graft survival in some studies (9)(10)(11), the mechanism by which this occurs is unknown. It is currently unclear whether obesity-related graft failure is mediated by the associated co-morbidities, such as hypertension and dyslipidaemia, jeopardising the graft, or whether factors specific to obesity, such as hyperfiltration and proteinuria, are implicated.…”

The Evaluation of the Renal Transplant Candidates: Clinical Practice Guidelines

“…The incidence of posttransplant diabetes mellitus is also higher in obese renal transplant recipients (909,911). Several transplant centers have reported increased immunological graft losses and decreased graft survival associated with higher mortality rates in obese renal transplant recipients (908)(909)(910)915). Other transplant centers, however, have not observed significant correlations between obesity and graft survival rates (911).…”

“…Probably as a result of this, a higher BMI has been associated with a reduced mortality among hemodialysis patients (906). In contrast, obesity is an important risk factor for renal transplant recipients and is considered by many transplant centers one of the exclusion criteria for renal transplantation for at least some individuals (907)(908)(909). Approximately 10-18% of transplant recipients have a pretransplant BMI Ø30 kg/m 2 (910,911).…”

Obesity and Kidney Transplantation

“…Overall mortality, regardless of obesity status, is substantially reduced with kidney transplantation (43,44). 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).…”

“…In transplant recipients, obesity is also associated with heightened risk of infections, and post-transplant diabetes (49)(50)(51)(52)(53). One single-center study which included 2013 adult kidney transplants performed between 1984 and 1998, superficial or deep wound infections occurred in 4.8%, whereas 3.6% developed either a fascial dehiscence or hernia of the wound (54). Those with BMI ≥ 30 kg/m 2 had a 340% increased risk for a wound infection and 182% increased risk for a fascial dehiscence or incisional hernia compared to those with BMI < 30 kg/m 2 .…”