Kidney Transplant After Bariatric Surgery

Background Obesity in kidney transplant (KT) recipients is associated with increased perioperative complexity and a higher risk of delayed graft function (DGF). Bariatric surgery is increasingly used in selected candidates, but real-world data on post-transplant outcomes and longitudinal renal function after prior bariatric surgery remain limited. Aims To compare early clinical outcomes, survival, and 1-year eGFR trajectories after KT across normal-weight, obese, and bariatric-history recipients. Methods We conducted a retrospective single-center cohort study including adult KT recipients transplanted between 01/2019 and 09/2024. Patients were stratified into Normal-weight, Adipose, and Bariatric-history cohorts. Baseline and perioperative variables are reported as median (Q1–Q3) or n (%). Group comparisons used Kruskal–Wallis and Pearson’s chi-squared tests. Outcomes included length of stay (LOS), DGF, and overall survival up to 36 months (Kaplan–Meier; log-rank). Post-transplant renal function was assessed by eGFR up to 1 year. Results A total of 348 recipients were included (normal-weight n=272, obese n=61, bariatric-history n=15). Age differed across cohorts (55 [39–65], 59 [54–67], 57 [48–59] years; p=0.014), while sex distribution was similar (female 33%, 38%, 47%). BMI differed markedly (24.0 [21.0–26.0], 33.0 [31.0–34.9], 29.8 [26.5–37.1]; p<0.001). Warm ischemia time differed (27 [23–31], 29 [24–32], 24 [21–29] minutes; p=0.041), whereas cold ischemia time did not (p=0.20). LOS increased with adiposity (5 [4–7], 7 [5–12], 6 [5–18] days; p=0.002). DGF occurred in 28%, 48%, and 47%, respectively (p=0.006). At 1 year, mean (SD) eGFR was 48.4 (19.7), 40.2 (13.0), and 43.6 (23.5) mL/min/1.73m², respectively. Estimated 36-month survival was 94%, 90%, and 93%, with no evidence of between-group differences (log-rank p>0.05). Conclusion Obesity was associated with higher DGF rates, longer LOS, and lower 1-year eGFR after KT. Recipients with prior bariatric surgery had comparable 36-month survival and intermediate renal function outcomes, although inference is limited by small sample size.