Obesity in kidney transplantation affects renal function but not graft and patient survival

Abstract

Introduction: The number of overweight and obese patients undergoing renal transplantation has increased dramatically over the past two decades. Studies on graft survival and posttransplantation complications have often yielded conflicting results. Some authors have reported similar results for graft and patient survivals between obese and normal weight patients, but with a marginally increased rate of postoperative complications. In contrast, other reports note higher percentage of graft losses as well as increased mortality. In our study, we analyzed early- and long-term outcomes among obese versus nonobese kidney transplant recipients.

Patients and methods: Between January 2000 and December 2008, we performed 563 cadaveric kidney transplantations. Recipients were classified in 1 of 5 groups based on their body mass index (BMI) at the time of transplantation: group A (n = 68; BMI < 18.5); group B (n = 310; 18.6 < BMI < 24.9); group C (n = 143; 25 < BMI < 29.9); group D (n = 32; 30 < BMI < 34.9); and group E (n = 10; BMI ≥ 35). The comparative analysis included patient and graft survivals, postoperative complications, onset of delayed graft function (DGF), acute rejection episodes, hospital stay, and serum creatinine values in the first 3 years posttransplantation.

Results: At a mean follow-up of 53 months (range, 3-112 months), DGF was observed in 20 patients in group A (29.4%), 82 in group B (26.4%), 43 in group C (30%), 16 in group D (50%), and 4 in group E (40%). Nevertheless, obese patients (groups D and E) showed higher mean serum creatinine values and worse renal function at 6 months (P = .001), 1 year (P < .001), and 3 years (P = .001). Moreover, they were at increased risk of an acute rejection episode (P = .01) and more susceptible to cardiovascular and metabolic complications (P = .01). Morbidly obese patients displayed a higher incidence of postsurgical complications (P = .002). There were no differences in the incidences of chronic allograft nephropathy (CAN) or infectious complications. Despite the differences in morbidity among the 5 groups, we failed to observe significant differences in patient or graft survivals at 6, 12, 36, or 60 months.

Conclusion: Our findings suggested that obese patients should not be discriminated against simply based on the BMI. At our center, obese (BMI >35) transplantation candidates undergo a thorough cardiac evaluation, as well as pulmonary, endocrine, and nutritional counseling seeking to minimize medical and surgical complications and improve survival and quality of life.