Effect of Changes in Body Mass Index on Cardiovascular Outcomes in Kidney Transplant Recipients

Background A higher body mass index (BMI) before kidney transplantation (KT) is associated with increased mortality and allograft loss in kidney transplant recipients (KTRs). However, the effect of changes in BMI after KT on these outcomes remains uncertain. The aim of this study was to investigate the effect of baseline BMI and changes in BMI on clinical outcomes in KTRs. Methods A total of 869 KTRs were enrolled from a multicenter observational cohort study from 2012 to 2015. Patients were divided into low and high BMI groups before KT based on a BMI cutoff point of 23 kg/m². Differences in acute rejection and cardiovascular disease (CVD) between the 2 groups were analyzed. In addition, clinical outcomes across the 4 BMI groups divided by BMI change 1 year after KT were compared. Associations between BMI change and laboratory findings were also evaluated. Results Patients with a higher BMI before KT showed significantly increased CVD after KT (P = .027) compared with patients with a lower BMI. However, among the KTRs with a higher baseline BMI, only persistently higher BMI was associated with increased CVD during the follow-up period (P = .003). Patients with persistently higher BMI had significantly decreased high-density lipoprotein cholesterol and increased hemoglobin, triglyceride, and hemoglobin A1c levels. Baseline BMI and post-transplantation change in BMI were not related to acute rejection in KTRs. Conclusions BMI in the 1st year after KT as well as baseline BMI were associated with CVD in KTRs. More careful monitoring of obese KTRs who do not undergo a reduction in BMI after KT is required.