Trends in epidemiology and risk factors of opportunistic infections in kidney transplant recipients between 2004-2022

Abstract Background While opportunistic infections are a frequent and challenging problem in kidney transplant recipients, their long-term epidemiology remains hardly known. Methods Opportunistic infections were recorded in 1144 recipients transplanted in our center between 2004 and 2015. Incidence rates and baseline risk factors were determined using joint frailty models. Results After a median follow-up of 5.6 years, 544 opportunistic infections occurred in 373/1144 (33%) patients, dominated by viral infections (396/544, 72%), especially CMV syndromes and diseases (213/544, 39%). A third of the infected patients experienced at least 2 opportunistic infections. The incidence of opportunistic infections was 10 times higher during the first year post-transplantation than afterwards (34.7 infections for 100 patient-years vs. 3.64). Opportunistic infections associated with the age of the donor (p = 0.032), the age of the recipient (p = 0.049), the CMV serostatus (p < 10−6), a higher class II HLA mismatch (p = 0.032), and an induction treatment including rabbit anti-thymocyte globulins (p = 0.026). Repeated opportunistic infections associated with each other (p < 10−6) and with renal death (p < 10−6). Conclusion Opportunistic infections occur with a 2-period incidence pattern and many susceptible patients suffer from repeated episodes. This knowledge may help tailor new prevention and follow-up strategies to reduce the burden of opportunistic infections and their impact on transplantation outcome.