Infection Risk in Older Kidney Transplant Recipients: An Analysis in the Era of Expanded Age Limits

The expansion of eligibility criteria has led to an increase in the age at kidney transplantation (KT), with consequences on the infection risk. We performed a prospective single-center cohort study of 712 patients undergoing KT between 2014 and 2022. Recipient age (median: 56.6 years [interquartile range: 43.2-68.5]) was analyzed by 10-year strata and dichotomized by thresholds (≥60, ≥70, ≥75 and ≥80). Univariable and multivariable regression models were constructed to assess the incidence of overall, bacterial and opportunistic post-transplant infection. In unadjusted analyses, each 10-year-increase was associated with overall (subdistribution hazard ratio [SHR]: 1.18; 95% confidence interval [CI]: 1.11-1.26), bacterial (SHR: 1.17; 95% CI: 1.09-1.26) and opportunistic infection (SHR: 1.26; 96% CI: 1.13-1.40). All groups >50 had an increased risk of infection. After multivariable adjustment, this association remained significant for overall (adjusted SHR [aSHR] per 10-year-increase: 1.09; 95% CI: 1.02-1.18) and bacterial infection (aSHR per 10-year-increase: 1.09; 95% CI: 1.00-1.18). Recipients ≥60 exhibited higher risk of overall infection (aSHR: 1.25; 95% CI: 1.00-1.54), and recipients ≥70 higher risk of opportunistic infection (aSHR: 1.54; 95% CI: 1.02-2.32). The incidence of infection was not significantly higher for patients ≥80 years. In conclusion, infection risk after KT increases with age, notably beyond 60 years.