The infectious disease burden in kidney transplant recipients: a 20-year multicenter cohort study on non-graft-failure hospitalizations in eastern China

Objective Kidney transplant recipients (KTRs) face significantly elevated hospitalization rates, with infections being a leading cause. This study aimed to comprehensively characterize the epidemiology, clinical outcomes, trends, and economic burden of non-graft-failure hospitalizations (NGFHs), with a particular focus on infectious diseases, in a large Chinese KTR cohort over two decades. Methods This retrospective multicenter cohort study included all adult KTRs under follow-up at three hospitals in eastern China from 2005 to 2024. Non-graft-failure hospitalizations were defined as admissions for indications other than permanent graft loss requiring return to maintenance dialysis or re-transplantation, and excluding routine surveillance biopsies. The primary outcomes were the causes and rates of hospitalization, length of stay (LOS), in-hospital mortality, and direct medical costs. Hospitalization rates per 100 person-years (PY) were calculated, and multivariable logistic regression with clustered robust standard errors and Firth’s penalized maximum likelihood estimation was performed to identify independent risk factors associated with in-hospital death. Results Among 202 KTRs (mean age 52.1 ± 13.8 years; 60.9% male), 384 NGFHs occurred over 1,814 PY. Among the 202 patients, 128 (63.4%) had a single hospitalization, while 74 (36.6%) had two or more admissions. The overall rate of 21.2 per 100 PY—approximately six-fold higher than previously reported rates for the age-matched general population. Infections were the predominant cause, accounting for 42.2% of all admissions, with pneumonia (9.4%) and urinary tract infections (7.0%) being most frequent. The in-hospital mortality rate was 2.9% ( n = 11), and all deaths occurred during infection-related admissions. Sepsis at admission was the strongest independent predictor of death (adjusted OR 34.2, 95% CI 7.8–150.1; sensitivity analysis using Firth’s penalized regression: OR 29.6, 95% CI 8.2–106.5). Deceased patients had significantly longer LOS (median 24 vs. 4 days) and higher costs (¥92,922 vs. ¥7,896; both p < 0.001). The overall hospitalization rate declined after 2015 (24.6 → 17.8/100 PY), driven largely by fewer infection-related admissions. Conclusion Infectious diseases are the leading cause of non-graft-failure hospitalizations and all in-hospital deaths in this cohort occurred during infection-related admissions. Sepsis at admission is a critical prognostic sentinel, mandating immediate protocolized recognition and escalation of care. The post-2015 decline in infection-related admissions provides hypothesis-generating, real-world evidence consistent with the potential effectiveness of multi-modal prevention strategies, which warrant further evaluation.