Pretransplant BMI Should Be <25 in Japanese Kidney Transplant Recipients: A Single-Center Experience

Abstract

Background: The aim of this study was to determine the appropriate body mass index (BMI) in Japanese kidney transplant (KTx) recipients. We analyzed the effects of pre- and post-transplant (Tx) obesity on graft and patient survival, perioperative complications, post-transplant diabetes mellitus (PTDM), and cardiovascular disease (CVD) in Japanese KTx recipients.

Methods: This retrospective study included 269 recipients who underwent KTx from 2008 through 2020 at Niigata University Hospital. Obesity was defined as a body mass index (BMI) ≥25 kg/m². We examined the association between pre- and post-Tx obesity and graft survival, patient survival, the incidence of PTDM and CVD, and perioperative surgical complications.

Results: The graft survival rate was lower in the pre-Tx BMI ≥25 kg/m² group, although there was no significant difference in patient survival. There was no difference in graft and patient survival between the post-Tx BMI ≥25 kg/m² group and the <25 kg/m² group. A pre-Tx BMI ≥25 kg/m² was an independent risk factor for biopsy-proven allograft rejection. New-onset DM after transplantation was significantly more common in the BMI ≥25 kg/m² group than in the BMI <25 kg/m² group (36% vs 13%; P = .002). The incidence of CVD was significantly higher in the post-Tx BMI ≥30 kg/m² group than in the BMI <30 kg/m² group (50% vs 11%; P = .023). There were no differences in surgical operating time, intraoperative blood loss, or perioperative complications between the obese and non-obese groups.

Conclusion: Pre-Tx BMI ≥25 kg/m² may be a risk factor for allograft rejection and graft loss. Post-Tx BMI should be <25 kg/m² to reduce the risk for PTDM.