Burden and Outcomes of Gastrointestinal Complications After Kidney Transplantation: A Retrospective Event-Based Study

Introduction Gastrointestinal complications (GICs) are common after kidney transplantation (KT) and may compromise graft function. Our study aimed to determine the prevalence of acute GICs, identify the associated risk factors, and evaluate their impact on graft survival. Methods We conducted a retrospective study including patients who experienced an acute GIC defined as any acute digestive event lasting less than 14 days after KT. We included infectious or drug-induced diarrhea, gastrointestinal bleeding, and surgical abdominal complications. Patients with chronic gastrointestinal or hepatic diseases were excluded. As multiple GICs could occur in the same patient, the analysis was performed at the event level. A logistic regression analysis was conducted to identify factors associated with graft dysfunction, defined as an estimated glomerular filtration rate (eGFR) < 60 mL/min/1.73 m² at three months following a GIC. Results Fifty-three patients experienced at least one GIC, corresponding to a prevalence of 46.9%, with a total of 84 events recorded. The mean age was 50 ± 13.3 years, with a male-to-female ratio of 1.52. The mean time to onset was 34.5 ± 46.1 months. Acute diarrhea was the most frequent complication (85.71%), which was of infectious origin in 79% and drug-related in 21%. Hemorrhagic complications accounted for 10%, including five cases of hematemesis and four cases of rectal bleeding. Three surgical complications were identified: appendicitis, colonic obstruction, and cholecystitis. From a renal perspective, 47% of patients developed acute kidney injury (AKI), and 20% progressed to graft dysfunction. The occurrence of AKI had a significant impact on six-year graft survival (p = 0.002). In univariate analysis, AKI (OR = 18.75, 95% CI = 3.60-97.5, p < 0.001) and recurrent diarrhea (OR = 2.91, 95% CI = 1.29-6.55, p = 0.010) were significantly associated with graft dysfunction. In multivariate analysis, both AKI (adjusted OR = 41.69, 95% CI = 4.75-365.82, p < 0.001) and recurrent diarrhea (adjusted OR = 3.62, 95% CI = 1.01-13.04, p = 0.049) remained independent predictors of graft dysfunction following GIC episodes. Conclusion Infectious diarrhea is the most common GIC after KT. AKI is the main determinant of graft dysfunction and graft survival.