Body Mass Index Thresholds and the Use of Bariatric Surgery in the Field of Kidney Transplantation in Germany

Abstract

Background: Obesity in the recipient is linked to inferior transplant outcome. Consequently, access to kidney transplantation (KT) is often restricted by body mass index (BMI) thresholds. Bariatric surgery (BS) has been established as a superior treatment for obesity compared to conservative measures, but it is unclear whether it is beneficial for patients on the waiting list.

Methods: A national survey consisting of 16 questions was sent to all heads of German KT centers. Current situation of KT candidates with obesity and the status of BS were queried.

Results: Center response rate was 100%. Obesity in KT candidates was considered an important issue (96.1%; n = 49/51) and 68.6% (n = 35/51) of departments responded to use absolute BMI thresholds for KT waiting list access with ≥ 35 kg/m² (45.1%; n = 23/51) as the most common threshold. BS was considered an appropriate weight loss therapy (92.2%; n = 47/51), in particular before KT (88.2%; n = 45/51). Sleeve gastrectomy was the most favored procedure (77.1%; n = 37/51). Twenty-one (41.2%) departments responded to evaluate KT candidates with obesity by default but only 11 (21.6%) had experience with ≥ n = 5 transplants after BS. Concerns against BS were malabsorption of immunosuppressive therapy (39.2%; n = 20/51), perioperative morbidity (17.6%; n = 9/51), and malnutrition (13.7%; n = 7/51).

Conclusions: Obesity is potentially limiting access for KT. Despite commonly used BMI limits, only few German centers consider BS for obesity treatment in KT candidates by default. A national multicenter study is desired by nearly all heads of German transplant centers to prospectively assess the potentials, risks, and safety of BS in KT waitlisted patients.

Keywords: Bariatric surgery; End-stage renal disease; Kidney transplantation; Obesity.

Fig. 1

Center response rate shown as total and divided into nephrology and surgery

Fig. 2

Survey questions and responses shown as total numbers or % (A Does obesity in ESRD patients present a relevant issue in your center? B Does your center have a policy or standard operating procedure for ESRD patients with obesity regarding inclusion on the kidney transplant waiting list? C What is the upper limit BMI at your center for considering patients with ESRD for kidney transplantation evaluation? D What BMI is the upper sole exclusion criterion for patients with ESRD to be eligible for kidney transplantation [status “transplantable”] at your center? E Does the BMI present an appropriate criterion for the selection of potential kidney transplant candidates? F If not, which of the following parameters do you consider as better criteria? [Multiple answers possible])

Fig. 3

Survey questions and responses shown as total numbers or % (A Are weight loss programs useful measures for patients with obesity before kidney transplantation? B Which weight reduction measures do you consider appropriate in ESRD patients to treat obesity prior to kidney transplantation? [Multiple answers possible] C Which weight loss measures does your center offer to ESRD patients with obesity in preparation for kidney transplantation? [Multiple answers possible] D Do you treat all waiting list patients, who are above the BMI threshold with bariatric surgery at your center? E Which bariatric surgery is the most suitable in the context of kidney transplantation?)

Fig. 4

Survey questions and responses shown as total numbers or % (A What may be the benefits of bariatric surgery before kidney transplant? [Multiple answers possible] B What concerns do you have about bariatric surgery in the context of kidney transplantation [Multiple answers possible] C How many patients underwent kidney transplantation after bariatric surgery at your center? D Are you interested in participating in a prospective multicenter study on obesity in the context of kidney transplantation?)