One-year infection outcomes in simultaneous pancreas-kidney versus kidney transplantation alone in diabetic recipients: a retrospective cohort study

Simultaneous pancreas-kidney transplantation (SPK) restores euglycemia and improves survival compared with kidney transplantation alone (KTA) in patients with diabetes and end-stage renal disease. Whether this greater surgical and immunological burden translates into a clinically meaningful excess of infections during the first post-transplant year, or into impaired one-year graft outcomes, has not been examined in a cohort combining detailed infection phenotyping with multivariable adjustment. This single-center retrospective cohort study included 228 SPK and 98 KTA recipients with diabetes who underwent transplantation between January 2019 and June 2025. The primary endpoint was infection-related hospitalization within 12 months. Secondary endpoints were bacteremia, site-specific infections, cytomegalovirus (CMV) DNAemia, Pneumocystis jirovecii pneumonia (PJP), and one-year patient and graft survival. Analyses used multivariable Cox regression, Kaplan-Meier estimation, and a Fine-Gray competing-risk sensitivity analysis. Infection-related hospitalization was more frequent after SPK than after KTA (0.54 vs. 0.31 episodes per person-year; IRR 1.76, 95% CI 1.22–2.57; p = 0.003). Bacteremia occurred at 0.10 versus 0.01 per person-year (IRR 9.4, 95% CI 1.52–387.1; p < 0.001). Surgical-site and intra-abdominal infections predominated after SPK (18.9% vs. 3.1%; OR 7.36, 95% CI 2.23–24.34), whereas pulmonary infections were more common after KTA (25.5% vs. 7.9%; OR 0.25, 95% CI 0.13–0.49). CMV DNAemia developed in 53.5% of SPK recipients. In multivariable analysis, SPK with rabbit anti-thymocyte globulin induction remained associated with infection-related hospitalization compared with KTA with basiliximab (adjusted HR 1.6, 95% CI 1.0–2.5, p = 0.04). Patient survival at one year was similar (96.3% vs. 95.0%; p = 0.32), whereas death-censored kidney graft survival was higher after SPK (98.8% vs. 93.0%; p = 0.04); pancreas graft survival was 94.2%. Compared with KTA, SPK recipients had more early infections, predominantly surgical-site and intra-abdominal infections and bacteremia, without translating into worse one-year patient or kidney graft survival. CMV DNAemia preceded PJP in all affected SPK recipients, consistent with earlier reports that CMV is a dominant risk factor for PJP. In this cohort, extending PJP prophylaxis after documented CMV DNAemia was followed by no subsequent PJP cases; this preliminary observation warrants prospective validation. Not applicable.