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

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.