Do invasive fungal infections affect kidney transplantation outcomes?

Background Invasive fungal infection (IFI) is a serious complication after kidney transplantation, but its longitudinal association with transplant outcomes remains unclear. We evaluated longitudinal associations of post-transplant IFI with subsequent outcomes, including how this association varied over time and by onset timing and IFI type. Methods We conducted a single-center retrospective cohort study of 752 adult kidney transplant recipients transplanted in 2020–2023 and followed through December 31, 2025. First post-transplant IFI was adjudicated using standardized definitions and modeled as a time-varying exposure. The primary outcome was the composite outcome of all-cause mortality or graft failure; secondary outcomes were all-cause mortality, death-censored graft failure, and acute rejection. Analyses included period-specific incidence-rate comparisons, an adjusted Cox model allowing the IFI-associated HR to vary over post-transplant time, sequential risk-set matching, and competing-risk analyses. Results IFI occurred in 137 recipients (18.2%) at a median of 284 days (IQR, 132–366) after transplantation; Pneumocystis jirovecii pneumonia (PJP) accounted for 99 cases (72.3%) and invasive aspergillosis (IA) for 29 (21.2%). Incidence rates of the composite outcome of all-cause mortality or graft failure were higher during IFI-exposed than non-IFI person-time within 6 months after transplantation (IRR, 34.05; 95% CI, 15.80–71.64) and after 6 months (IRR, 8.80; 95% CI, 4.89–16.00; both P < 0.001). The adjusted Cox model showed a decreasing IFI-associated HR over post-transplant time (P for time variation = 0.002). IFI was also associated with all secondary outcomes. In the multivariable matched-cohort model, IFI remained associated with the composite outcome (adjusted HR, 10.83; 95% CI, 5.51–21.29; P < 0.001). Within-IFI analyses showed higher risks of the composite outcome and all-cause mortality with IFI onset ≤6 versus >6 months after transplantation and with IA versus PJP. Conclusions Post-transplant IFI was associated with adverse transplant outcomes, with a stronger association earlier in the post-transplant period. Among recipients with IFI, onset within 6 months after transplantation versus later onset and IA versus PJP were associated with poorer outcomes. These findings warrant multicenter validation.