De novo belatacept-based immunosuppression is not associated with increased risk of invasive fungal infection in kidney transplant recipients.

The risk of invasive fungal infection (IFI) in kidney transplant recipients (KTRs) receiving de novo belatacept-based immunosuppression remains incompletely understood. We conducted a single-center retrospective cohort study of adult KTRs receiving de novo belatacept- or tacrolimus-based immunosuppression between 2016 and 2025. Cumulative incidence of IFI was estimated using competing-risks methods with death as a competing event and compared using Gray's test. Associations between immunosuppression and IFI risk were evaluated using a cause-specific Cox model, with thymoglobulin and high-dose steroids modeled as time-dependent covariates. A prespecified propensity score-matched cohort was analyzed to address selection bias. Associations between IFI and mortality were assessed using time-dependent Cox proportional hazards models. Among 2729 KTRs, 1875 (68.7%) received belatacept and 854 (31.3%) tacrolimus. The 1-year cumulative incidence of IFI was 1.4% in belatacept-treated patients vs 1.8% in tacrolimus-treated patients (P = .47). Belatacept compared with tacrolimus was not associated with IFI (hazard ratio, 0.87; 95% confidence interval, 0.54-1.39). IFI was associated with mortality (hazard ratio, 5.03; 95% confidence interval, 3.12-8.09). Similar results were observed in the propensity score-matched cohort. De novo belatacept-based immunosuppression does not confer increased risk of IFI, and routine antifungal prophylaxis may not be necessary.